Widespread flooding in New Zealand on the weekend of April 20/21 will be an insurance event, with businesses and insurers still calculating losses.

Insurance losses in the South Island city of Nelson are expected to top the $NZ16 million ($13.1 million) cost of the December 2011 floods in the area, with more businesses affected this time, Insurance Council of New Zealand CEO Tim Grafton told insuranceNEWS.com.au.

Losses are still being calculated from flooding in the Bay of Plenty.