Watch: Prime Minister Chris Hipkins gives latest update of Cyclone Gabrielle aftermath

People should be prepared for the number of fatalities in the wake of the cyclone to increase, the prime minister says.

Chris Hipkins is speaking to media from Wellington, and says every available resource is being used to help find those who are missing and to rescue those who are known about but unable to be reached.

Over the past two days the rescue coordination centre had overseen 450 rescues and all rescue requests in the 111 system had been completed, Hipkins said.

As of 2.30pm, 3544 reports of uncontactable people had been registered with the police 105 function. A further 450 had been reported as found.

Those included multiple reports for the same people. Police were prioritising those in the more isolated areas.

It was important that as people were able to communicate and let others know they are OK, if they have been registered as missing, that they take the time to register their wellbeing online with police 105, he said.

The number of fatalities stands at five but there are still people for whom the police hold grave concerns.

"And we do need to be prepared for the likelihood that there will be more fatalities," Hipkins said.

The situation in Gisborne

Hipkins said the damage in Gisborne was extensive and there was "absolutely no doubt" that communities impacted were under enormous pressure.

Earlier, Hipkins flew to Gisborne for his first in-person look at the scale of destruction from the cyclone.

Hipkins said it "was a pretty moving morning".

"Flying in over Gisborne is was clear the extent of the damage even before we'd gotten off the plane."

It was clear there were big challenges facing the community, he said.

Communication was incredibly difficult for some people and both fibre routes in and out of Gisborne had been damaged with engineers working to repair the damage as fast as they could, Hipkins said.

Getting the water supply up and running would not be an overnight fix but was a prority, he said.

Hawke's Bay update

The government was trying to get hotspots and other temporary measures in place and 10 more Starlinks were on their way to Gisborne. Five units have been delivered to Wairoa and Hawke's Bay, with more on the way.

Hipkins said there was a reasonably good supply of Starlinks in NZ.

"They're not going to provide a complete answer though, but they will provide a limited amount of connectivity in those areas that are currently cut off and that will hopefully allow us to at least establish some of those basic communication channels...

"We've been able to reach Wairoa and Hawke's Bay by road today and SH2 to Gisborne has also been opened on a limited basis for convoys of emergency supplies including food, water and fuel."

Temporary supplies were on route and more would be arriving soon, he said.

"Fresh water is clearly an issue."

There were real concerns for the Eskdale areas, Hipkins said.

Teams were there going doo-to-door to identify the extent of the damage and any human harm, he said. There had not been a report back from these teams yet.

People in Hawke's Bay were advised to be prepared. "We're dealing with very unpredictable weather at the moment, it is certainly likely that there will be more rain, that's what the forecasts are suggesting."

The damage to roads in all areas was one of the most significant challenges and people in these areas were asked to minimise their own movements so supplies could get to where they were needed, Hipkins said.

"If you can stay put, stay put, make sure you've got everything you need to stay put if it's safe to do that and if you need to evacuate be prepared and be ready to evacuate as well.

"That involves your grab to go bag, making sure you've got something warm and dry to wear and that you've got a plan."

Communities awere coming together and managing the situation very well, Hipkins said.

People may need to go door-to-door to alert others if they need to evacuate, Hipkins said.

"Encouragingly, every region now has an alternative route that allows us to get lifelines into them."

"Everything possible is being done to bring back power to those areas that have been hard hit by the cyclone."

The most recent information is that approximately 102,000 customers are without power across the upper North Island.

Hipkins said the government had released $1 million as an immediate top up to the mayoral relief fund as the first step to help get immediate support to those who need it.

A further $1 million had been released to the Hawke's Bay.

Police are sending an additional 100 staff into Tairāwhiti and Hawke's Bay areas.

The police eagle helicopter will be deployed tomorrow.

Many local police had been the first responders in many communities, Hipkins said.

"I just want to acknowledge how difficult it is for those communities who have been affected by this weather event. The sorts of things they were reporting back to me included that they felt very isolated, they felt very alone. That unfortunately is the nature of the initial days in some of these events but I just want to acknowledge how hard it's been for them."

"I think now that we can connect with them more easily, we can get more support to them."

Speaking about the siuation in general, Hipkins said: "As I indicated earlier today, we're also going to have to think about the longterm implications of this. We have some infrastructure in New Zealand that we're going to need to look very closely at, we're going to need to think about our roading network, our telecommunications network, our energy distribution networks and make sure we have them as robust as possible.

"We are going to see more of these types of events and making sure that we are prepared for them is going to require a significant amount of time, energy and investment."

NEMA efforts

NEMA has accepted an agency to agency offer from Australia for emergency response support and expertise.

Over the next 48 hours, five impact assessment teams made up of around 25 people will arrive in NZ to work with the FENZ and USAR teams.

The Australian team will search for people and look at how buildings are impacted.

"This is a complex and dynamic response, some areas, such as Auckland, Waikato, Thames-Coromandel, Bay of Plenty and the Manawatu and Whangarei, are fortunate to be scaling down their civil defence response and they're able now to move into the recovery phase."

Others, like in Gisborne and Hawke's Bay need the basics like food and water "and are still very much in the emergency response phase".

All hospitals in the impacted regions are open and functioning well. Additional blood, oxygen and other critical supplies have been flown in to Gisborne and Hawke's Bay.

Defence Force response

Air Commodore Darren Webb said the focus of the Defence Force had been the extensive support of NEMA.

Currently, 700 defence force members have been deployed with hundreds more on standby.

Two ships, 58 army vehicles, including two light armoured vehicles, six NH90 helicopters, two C130 transport aircraft, a seasprite helicopter and a Defence Force demand team have been deployed.

"Our priorities have been on saving people from immediate danger, helping authorities gain more knowledge in what is an ever-evolving situation and helping to support and respond to any ongoing relief efforts."

The people of the Defence Force lived in the communities they served so took a great deal of pride in being able to assist friends and whānau in their time of need, he said.

There had been an intensive effort in the Tairāwhiti and Hawke's Bay regions, he said.

Emergency communication links have been established in Hawkes Bay and Gisborne, a range of reconnaissance tasks have been conducted to help build a better picture of the damage and food, water and shelter have been provided to isolated communities.

Military water treatment plants have been moved to Wairoa and Gisborne. They can produce up to 3000 litres of fresh water per hour.

HMNZS Manawanui has arrived in Tairāwhiti coastal region and has dropped off food and water in Tokomaru Bay.

The ship was expected to reach Tolaga Bay this evening.

It is due into Gisbone tomorrow morning to assist the community. Another ship departs Auckland for Napier, with a 25 person response team and humanitarian supplies on board.

The army has more people to deploy if needed, and two light armed vehicles are checking a road route to Gisborne right now to possibly move in a larger water treatment plant that cannot be moved by air.

A second water treatment plant will move to Gisborne and two Transpower 4x4 vehicles and crews will be moved to Kerikeri.

The helicopters will move a small military water treatment plant as well as army into Wairoa.

"This has already been one of our largest domestic deployments in recent memory and we will continue to support those in need for as long as it takes."

Webb said the support offered by NZDF was meeting all needs coming in from NEMA but a needs assessment was being done to determine if there was any specific capabilities needed from international partners.

"But at this point in time, we're currently OK."

National Emergency Management Agency advice:

• Put safety first. Don't take any chances. Act quickly if you see rising water. Floods and flash floods can happen quickly. If you see rising water do not wait for official warnings. Head for higher ground and stay away from floodwater.
• Do not try to walk, play, swim, or drive in floodwater: even water just 15 centimetres deep can sweep you off your feet, and half a metre of water will carry away most vehicles.
• If you have evacuated, please stay where you are until you are given the all-clear to go home.
• If you don't need to evacuate, support those who do by staying home, staying off roads and staying safe.
• If you are not able to contact your whānau in the heavily affected areas go to Police 105 website and complete the inquiry form or phone 105 and remember to update if you reconnect through other means.
• Throw away food and drinking water that has come into contact with floodwater as it is often contaminated and can make you sick.
• If you are without power eat the food from your fridge first, then your freezer. Then eat the food in the cupboard or your emergency kit.
• People should stay up to date with the forecasts from MetService and continue to follow the advice of civil defence and emergency services.
• A National State of Emergency is in place for an initial period of seven days and applies to regions that have declared a local State of Emergency.