A biosecurity clampdown is in place in Whangarei after the discovery of another Queensland fruit fly, prompting a call for a ban on importing fruit from some Australian states and tougher screening measures.
The male fruit fly was found on Tuesday in a surveillance trap in the harbour suburb of Parihaka and caught just 400 metres from where another was discovered in January this year. The destructive pest makes fruit and vegetables inedible and if it became established in New Zealand, there are fears it could cripple a $4 billion export industry.
The Ministry of Primary Industries (MPI) is setting more traps in Parihaka and Riverside, alerting residents of the find and imposing some restrictions on the movement of fruit and vegetables around Whangarei.
The Labour Party's spokesman for primary industries, Damien O'Connor, said on Thursday the ministry has failed to discover how the insects are getting into the country - and that's bad news and a massive failure for New Zealand's biosecurity.
Mr O'Connor said the latest incursion shows there is a pathway for the pest into the Northland town and the Government's lack of action is putting the horticulture sector in grave danger.
"I think we should halt the importation of high-risk fruit from Queensland, from New South Wales where the fly is now, until we know how the fly came in."
Mr O'Connor said the ministry needs to do more to stop it getting to New Zealand in the first place.
In a statement, the MPI acknowledged there has been an explosion of Queensland fruit flies in Australia in recent months and it had begun to review import requirements for high-risk fruit.
But Mr O'Connor said that's not good enough and if the fruit fly gets established in New Zealand, it would cost the horticulture sector billions of dollars.
Horticulture New Zealand chief executive Peter Silcock said the industry has confidence that the ministry is doing everything it can in terms of an international response to the incursion.
However, Mr Silcock told Radio New Zealand's Checkpoint programme that greater scrutiny would reassure the industry, and it wants more checks on people flying into the country from Australia - including more X-raying and greater use of dogs.
"There's no doubt that there's more fruit flies in Australia now than there ever was before, and that's got to do with the Australian governments, particularly in New South Wales and Victoria reducing their management of fruit fly."
Listen to report
Listen to Peter Silcock
Overseas markets alerted
Minister for Primary Industries Nathan Guy says New Zealand's international markets have been alerted about the latest discovery and it is important now to maintain their trust.
"That's why our posts were working with them overnight. We follow international best practice - that's over a couple of weeks of more intensive trapping, that's collecting fruit from fallen trees in the different zones."
Mr Guy believes banning fruit from Australia would be a "complete over-reaction", saying it would push up fruit and vegetable prices and encourage other countries to retaliate with their own trade restrictions.
"The MPI will do a thorough review and try and establish where the fruit fly has come from. You need to understand there's 175,000 items that come across our border a day, 10 million passengers in and out across our borders a year and there are a variety of pathways whether it's sea freight, small craft, mail, passenger pathway."
Ministry spokesperson Andrew Coleman said it is vital to find out if the insect is a solitary find or if there is now a wider population in the town.
The insect has been found four times in New Zealand previously, including the Whangarei discovery in January, but increased trapping in each case found no further flies. Mr Coleman said the most likely way that fruit fly can arrive in New Zealand is in fresh fruit and vegetables.
Listen to Checkpoint interview with Andrew Coleman
Ministry 'needs to join the dots'
The Whangarei suburb of Parihaka is close to the Town Basin marina, which hosts dozens of visiting international yachts every summer.
Former solo round-the-world yachtswoman Margaret Hicks said the Ministry for Primary Industries needs to start joining the dots and all boats coming from Queensland should be fumigated on or before arrival in New Zealand.
"I think it's too much of a coincidence that each time the fruit flies have been found on that side and it would be very easy for a fruit fly to transit the Tasman on a yacht."
Ms Hicks said there has been an epidemic of fruit fly in Queensland recently and it's only a matter of time till a female insect jumps ship in New Zealand.