New Zealand's recovery from Cyclone Gabrielle has passed a mighty milestone, with police clearing the long list of people reported as uncontactable in the storm's wake.

However, the country remains in a state of national emergency four weeks after Gabrielle's arrival, with the removal of silt looming as the next major challenge.

The death toll is 11, nine from North Island's eastern regions of Hawke's Bay and Tairawhiti, and two from the west coast of Auckland.

Police have announced the number of people recorded as uncontactable, which once stood over 6000, is now at zero, meaning early fears of a ballooning death toll have not been realised.

"It's a phenomenal effort from the police," Emergency Management Minister Kieran McAnulty said.

A 100-strong team worked remotely to gauge the whereabouts of missing Kiwis, with on-the-ground search and rescue crews and police assisting those enquiries and whittling down the list.

Nine days ago, police announced they were down to four uncontactable people, three of whom were wanted on active charges.

"They've had to really work hard to find those final few. Some may not have wanted to be found because it was the police that were looking for them. But they've got those numbers down here so good on them," Mr McAnulty said.

New Zealand is now in a hybrid response and recovery phase to its biggest storm in generations, with some regions still cleaning up, and others progressing with rebuilding.

Including the Auckland flooding from a fortnight prior to Gabrielle, 846 properties have been rendered uninhabitable, or "red-stickered".

There are still 200 displaced people staying at community centres, such as marae, and 1226 households remain without power.

For many flood-hit regions, the biggest task is the removal of silt.

Across Hawke's Bay, on productive land where orchards and vineyards once sat, there is instead huge quantities of earth repositioned from floodwaters.

"It's a massive problem," Mr McAnulty said.

"It's hard to even just explain how big of an issue this is. We're talking about some areas that have got silt that's eight feet high."

Mr McAnulty said the central government stood ready to fund silt removal, with councils too small to fund the job themselves.

"It's not going to be cheap. We've said we'll help where we can."

Cyclone Recovery and Finance Minister Grant Robertson, tallying the cost of the overall response ahead of the budget, has cooled on earlier projections the storm could cost as much as the 2011 Canterbury Earthquakes.

Those earthquakes, which killed 186 people, cost the government $NZ17.1 billion ($A15.8 billion), while the 2016 Kaikoura earthquake cost roughly $NZ3 billion ($A2.8 billion).

"We're probably closer to Kaikoura-level cost than we are to a Canterbury-level cost. But we are still pulling in that data," he said.

Mr Robertson said the government would look to spread recovery costs over several years, with major announcements expected in the May budget.