The first tropical cyclone has formed overnight in the southwest Pacific, and some models have it tracking directly on to New Zealand just before Christmas.
Niwa forecasters says Cyclone Yasa is currently lying between Vanuatu and Fiji.
Weatherwatch.co.nz says it will spend the next few days spinning around in a giant circle gaining strength. It is expected to go from a category 1 storm to category 3 by the time it brushes past Fiji on Wednesday.
While Fijians are being put on alert, Weatherwatch says modelling from various agencies show a 40 percent confidence Yasa could make it to New Zealand around a week from now.
One scenario has the potentially destructive cyclone off Northland and veering down on to the top of the country on Monday.
"WeatherWatch has about 40 per cent confidence this low will make it to New Zealand, probably one week from now. However, the storm will be going through a major structural change at this point which means a number of future scenarios are possible from a serious major hit, to a weak low that only brings some rain, to one that falls apart and misses NZ entirely."
The confidence level was based on modelling from various agencies over the past several days and reflected our current confidence, said Weatherwatch.
In October Niwa warned the country faced slightly higher odds of experiencing an ex-tropical cyclone over the next six months, on the back of warmer seas and a building La Nina climate system.
Each season - usually around late summer - at least one of these wild and destructive systems travels within 550km of New Zealand, packing high winds and heavy rain.
This season, Niwa is forecasting the potential for two.
Meanwhile, today marks a stretch of golden weather with a high settling over both islands for the coming week.
Some parts are expected to hit 30C and higher, with Christchurch expected to swelter on Wednesday and Saturday.
