Insurance companies are expecting up to several thousand claims to be lodged as a result of the Dunedin floods.
Record rainfall - 175 mms in 24 hours - last week caused widespread flood damage of at least 170 homes and shops in south Dunedin.
Insurance Council chief executive Tim Grafton said insurers were expecting claims for water-damaged house contents, as well as structural damage from flooding and slips.
"This will be a multi-million dollar insurance claim event, and we would expect hundreds, if not a few thousand, of claims to come in from it. Far too early for us to be able to estimate what the cost will be, but a very significant event, and a costly one too."
Mr Grafton said the total bill for claims would be known in six weeks.
Dunedin Council has urged residents to throw out damaged carpets due to concerns over contamination with sewage or heavy metal residues and to make an insurance claim.
Insurance Council and NIWA records show damage from Dunedin's last big flood in April 2006 cost insurers and councils at least $8 million.