Tropical Cyclone Vaianu forming in the Pacific could bring life-threatening winds and heavy rain to New Zealand later this week, forecasters have said, with strong wind watches issued for the entire North Island.

The category 3 cyclone is moving south of Fiji towards New Zealand, with winds around the centre in excess of 150km/h, MetService said on Wednesday.

While uncertainty remains over the cyclone’s track, MetService said it was increasingly likely it would reach New Zealand on Sunday, bringing with it “damaging, potentially life-threatening winds”, heavy rains and hazardous coastal conditions.

While the heaviest rain is expected across the north and east of the North Island, the storm could affect large parts of New Zealand, MetService said.

Meteorologist John Law said: “We have several days until we see the impacts of Vaianu on New Zealand so this is an early severe weather watch, a heads-up for significant weather this weekend.”

Severe weather watches are normally issued one to three days before a weather event and the longer lead time of these watches is an indication of the potential severity of the event, Law said.

As the forecast becomes clearer, the watch could be upgraded to a severe weather warning.

A second severe tropical cyclone named Maila was upgraded to a category 5 system on Wednesday, with winds near the centre of 215km/h and wind gusts up to 295km/h.

The cyclone was located in the Solomon Sea and is moving towards the far north Queensland coast. It would not affect New Zealand, MetService said.

New Zealand has faced several severe storms this year. In January, a series of tropical storms swept through the North Island, bringing torrential rain and causing two fatal landslides. In February, storms caused flooding, landslides and power outages across the country.

In 2023, tropical Cyclone Gabrielle was the worst storm to hit New Zealand this century, killing 11 people, causing a global record of about 850,000 landslides and becoming the most expensive weather-related event in the country’s history.