The worst of Cyclone Cook is over, leaving some wondering: "Was that really it?"

Forecasts said the storm would be the worst since 1968, when Cyclone Giselle sank the Wahine in Wellington's harbour. Auckland and Wellington were reportedly in its path, so city folk left work early, secured their trampolines, and waited.

The New Zealand Transport Agency warned an "unprecedented" closing of Auckland's Harbour Bridge was possible.

"I have never seen an event like this in the 12 years I have been a forecaster in New Zealand ... this is not an event to be taken lightly," MetService forecaster Lisa Murray said on Wednesday.