Tropical cyclone weakening but may still bring bad weather

A tropical cyclone that lashed a small community of scientists on Raoul Island last night is set to bring strong winds and rain to New Zealand.

But MetService predicts the storm will not be strong enough to cause "warning level" severe weather by the time it reaches Gisborne and the East Cape tomorrow.

Tropical Cyclone Bune knocked out seismographic and meterological equipment and caused a storm surge when it hit the small island about 1100km north-east of the North Island, which is home to about 10 scientists, at about 6pm last night.

WeatherWatch.co.nz head analyst Philip Duncan said the cyclone has remained a powerful Category 2 strength storm, with sustained winds of 110km/hr.

Though it was likely to decay before reaching Gisborne and the East Cape on Wednesday, it could still bring severe weather, he said.

He warned of dangerous seas and a 60 per cent chance of heavy rain in the area.

"Despite it going through extra-tropical transition... it is still a dangerous storm and is already bringing rough surf, seas and rips to the east coast."

MetService said the ex-cyclone would form a deep low off the coast Gisborne.

Strong southerlies and some rain were expected in Gisborne tomorrow and Thursday morning, but the weather was increasingly unlikely to be severe, its forecast said.

Its weather ambassador Bob McDavitt advised boat owners in Northland, western Bay of Plenty, Gisborne and Hawkes Bay to check their moorings before the cyclone arrived.

"Long-period swells associated with the system are likely to cause problems.

"Waves will probably be large enough in some places to pose a danger to swimmers,cause coastal erosion and test the soundness of moorings."