Redclyffe substation was significantly affected by the flooding. Photo: RNZ/Lauren Crimp
Network company Unison said it will be months before power is restored in some rural Hawke's Bay communities.
At the flood-ravaged Redclyffe substation outside Taradale, chief executive Ken Sutherland said Unison was throwing "everything" at the effort to restore power in the region.
Part of the problem was getting access to those rural communities.
"We're flying crews in on the other side of the bridges that are out to get Tutira back up and going, and we're doing the same elsewhere across the region."
The substation was under water. Photo: Transpower
Sutherland said they had been well supported by the industry across the country.
But the scale of the challenge was significant, he said.
"This is bigger than Bola.
"We've had other cyclones that come through and storms, that we've been able to get things up and going within three weeks. This is a magnitude higher than that, so this is going to be a significant amount of effort over a long period of time."
Sutherland said people needed to understand a "massive amount" of infrastructure across a wide area was affected.
"They need to know that we're trying to get the power back on as fast as possible, Transpower's doing that, we're doing that, we're getting support from the other regions to do that."
Finance Minister Grant Robertson visited the substation on Sunday. Photo: RNZ/Lauren Crimp
Sutherland said once the work was complete, the industry would need to consider what could be done better - including reviewing the location of Transpower's Redclyffe substation, which is on a flood plain.
"The substation's not in an ideal place, but that's not easy just to pick up a substation and move it, but ideally we'd like it in a different place.
"We need to look at resilience across other substations, so having a critical importance on Redclyffe is probably not the best idea, so having some diversity to supply Hawke's Bay better."