Heavy rain and gales are predicted as a band of rain moving south from the tropics sets its sights on New Zealand.

And there are concerns that the weather system could bring waves more than 7m high to the Bay of Plenty - potentially causing another oil leak from the Rena.

Forecasters are divided over whether the bad weather on its way is stretching down from Fiji, which is being battered by a deadly storm which has caused severe flooding and widespread devastation.

MetService has issued a severe weather warning for Gisborne and the Hawkes Bay, and a severe weather warning for Northland, Coromandel Peninsula, Bay of Plenty, Taupo and Taranaki, with heavy rain predicted potentially causing slips, surface flooding and hazardous driving conditions.


In the 42 hours from 9am today, Gisborne may get up to 160mm of rainfall, while the ranges of Hawkes Bay may get 130mm in the 27 hours from 9pm.

Meteorologist Daniel Corbett downplayed the notion that the weather system was coming from Fiji and said it was rather coming "down from the tropics".

But WeatherWatch head analyst Philip Duncan said "relentless" gale-force winds would affect Waikato, East Coast, Gisborne and Hawkes Bay for six days, brought in by tropical storms connected to those hitting Fiji.

Heavy rain could cut off towns in already sodden areas of East Cape, while coastal communities could be affected by huge swells, he said.

"This storm system is literally stretching from here to Fiji ... It's just going to be relentless for the next six days. There's a high risk of landslides and a high risk of flooding.

"Communities could be isolated again. There's going to be this relentless wind that will be gale force."

Mr Duncan said the wreck of the Rena on Astrolabe Reef could be in the path of waves averaging 4m high.

Oceanographer Brett Beamsley said maximum individual waves could exceed 7m.


Maritime NZ national on-scene commander Rob Service said his team was ready to deal with another oil spill if it occurred.

Mr Duncan said Daphne, the category one cyclone that had formed to the west of Fiji, was heading to New Zealand, merging with lows on its way, but it wasn't as bad as it sounded.

"It will simply mean the energy will be spread further, which can sometimes reduce the severity but prolong the period of unsettled weather."

Mr Corbett also said Daphne's effect on New Zealand would be minimal.

"That will probably stay to the south of Fiji and some of that rain band may affect Fiji in the next 24 hours and that actual storm itself will probably be staying to the north and the east of New Zealand.

"That's not to say that some of that moisture might not creep into the flow that comes into New Zealand, but it wouldn't be a direct hit to New Zealand from that cyclone."


* Today: Rain, heavy falls. Strong southeast winds.
* Tomorrow: Rain periods, sometimes heavy. Strong easterlies.
* Thursday: Rain then showers, some heavy. Easterlies easing.

* Today: Rain becoming widespread. Strong southeasterlies.
* Tomorrow: Rain periods, sometimes heavy. Strong easterlies.
* Thursday: Rain then showers, possibly heavy. Easterlies easing.

* Today: Cloudy, afternoon rain. Strong or gale southeasterly.
* Tomorrow: Rain easing to showers. Southeasterlies.
* Thursday: Mostly cloudy, rain at times. Southeasterlies.

* Today: Occasional rain. Strong or gale southeasterly.
* Tomorrow: Rain easing to showers. Southeast gales.
* Thursday: Showers, some possibly heavy. Fresh southeasterlies.