High chance of cyclones this season

New Zealand's chances of being hit by a tropical cyclone on the scale of cyclone Bola or the Wahine storm are higher than normal this season, Metservice says.

Meteorologist Steve Ready said that was because the equatorial Pacific Ocean was in a "neutral" phase, neither El Nino or La Nina.

Mr Ready said in past years with similar conditions, New Zealand had experienced some of its most damaging storms including Gisele in April 1968 when the Wahine sank in Wellington Harbour, Bola in 1988 which caused widespread flooding in the Gisborne area and 1996 and 1997 when cyclones Drena and Fergus battered parts of the North Island.

"The risk is much higher than it has been in recent years, this is the season we really have to be more aware than others," he said.

Peak cyclone "season" in the South Pacific is usually January to March although cyclones can form any time from November to May.

Nine tropical cyclones were expected to form this season in the South Pacific near Vanuatu, the Coral Sea or Fiji. Around half could develop to hurricane strength.