Tropical depression TD04F developed into a tropical cyclone on 10 January, named Pita. Photo:
The risk of cyclones in Pacific Islands close to the coral sea could increase as a La Niña watch remains in place.
The first cyclone of the cyclone season, Pita, passed near Niue over the weekend.
La Niña refers to a cooling of the tropical Pacific Ocean, particularly near and east of the international date line.
It's the opposite to El Niño which was underway this time last year.
The south Pacific is currently in the middle of its cyclone season.
NIWA forecaster Chris Brandolino said the second half of the season from January is normally the most active.
"Areas in and around the coral sea, Vanuatu even maybe toward the Solomons, they run the higher risk for a tropical cyclone development as we work our way through the next few months.
"Areas further east, the risk is likely to be normal to even reduced."
He said rainfall could also increase in islands by the coral sea, with island nations further east like French Polynesia and the Cook Islands seeing less rainfall and experiencing drought.
"That's because that is where we're seeing ocean temperatures to be relatively cool. These cool ocean temperatures, they don't encourage rainfall - they favour dryness."
Brandolino said La Niña means "different things for different people".
He said trade winds would be blowing briskly over the next month in the tropical Pacific especially just west of the international date line.
"Just east of Fiji to maybe around the north of New Caledonia, in that zone nearer to the equator, the trade winds are going to be accelerating.
"People may notice fast or stronger trade winds and maybe higher waves with those associated with those trade winds."
