Northland councils say the damage to roads, bridges and sewerage systems caused by Cyclone Wilma is likely to exceed $10 million.
Torrential rain that fell on Friday and Saturday was heavier in some parts of the north than in the major floods of 2007.
Whangarei District Council is facing a damages bill of about $6 million, and the Far North at least $5 million.
The councils are eligible for government subsidies of up to 70%
Temporary clean-up work on slips and washouts in the Far North should be complete in a few days, but permanent repairs could take months.
Whangarei District Council is warning that many roads will be slippery and treacherous for the next fortnight as debris continues to fall from hundreds of slips.