The Earthquake Commission (EQC) has received at least 170 claims relating to residential land damage in the Napier flood.
The numbers are still rising with more than 20 of the claims to the Government agency made on Monday or Tuesday – a week or more after the storm - and insurers say it will be several weeks before the financial cost can be quantified.
By mid-afternoon Monday, 147 claims had been notified, but by early afternoon the number had risen to 170, a spokesperson said.
Based on costs of other recent rain-event disasters in New Zealand, the cost is likely to rise into the tens of millions of dollars.
In September the Insurance Council reported $37 million had been paid-out by insurers in respect of the Northland floods in July, and in May the insurers' costs for floods in Southland in February had passed $20 million.
The cost of the April 2017 Edgecumbe flood, in which the banks of the Rangitaiki River burst and flooded the town, destroying 15 homes and badly damaging at least 250 others, was several months later put at $64.7 million.
Traditionally the Insurance Council does not start releasing cost details until about six weeks after events.
EQC chief readiness officer Josh Lindsay said the claims received by the agency are made up by claims for land damage, as well as damage to residential properties caused by landslips.
Victims with residential home and contents insurance should be contacting their insurers, who notify EQC to support with any claims related to land damage such as slips or resulting silt or debris from either landslips or floodwaters.
Meanwhile, Ministry of Business Innovation and Employment (MBIE) Tenancy Accommodation Service (TAS) national manager Al Bruce has confirmed portable accommodation could be brought to Napier to help provide temporary homes for people displaced by the floods.
The TAS was activated on Monday, and Bruce says it has a fleet of purpose-built portable cabins for emergency responses that are "ready for deployment if necessary" when there is a shortage of other options.
"If this is the most suitable option for the needs of those affected. Prior to deploying the cabins, MBIE will consult with Napier City Council," he said.
"Wherever possible, TAS uses existing, undamaged residential housing supply as temporary accommodation," he said.
The MBIE is the agency responsible for co-ordinating provision of temporary accommodation for people who have to leave their homes as a result of an emergency.
"This temporary accommodation function is distinct from shelter and emergency accommodation, which is provided for short periods of up to two weeks by Civil Defence and emergency management agencies," he said.
He said TAS is working with local authorities in the region to assess damage and establish how many homes have been affected, adding: "It is clear assistance finding temporary accommodation will be required for a number of households."
Its matching and placing team will collect registrations from displaced people, establish what accommodation options are suitable, and "connect them together".
The service is considering supply options, and has two staff in Napier engaging with the community to assess the needs and provide the matching and placing service face to face.