Tropical cyclone may hit NZ few days before Christmas

Plans for a Christmas barbecue might fizzle out if a tropical cyclone headed our way hits close to the big day.

Weather authorities say computer modelling over the past few days has shown signs of a tropical cyclone threatening New Zealand in less than two weeks - and about a week away from the big day itself.

WeatherWatch analysts say it is still "very early days" but the computer modelling was one the authority trusts.

"Modelling for several days has pointed to a tropical cyclone forming around Vanuatu to Fiji area next week and drifting from east to west, towards the north Tasman Sea and New Caledonia area," a statement says.

"Over the coming week, we'll continue to monitor the models and tracking of this potential storm."

WeatherWatch said with the La Nina (dry) weather system, it was only a matter of time before a cyclone would develop north of the country, up in the southwest Pacific tropics.

Despite the potential threat of a cyclone dampening things ahead of Christmas Day, weather experts say a large high pressure system is expected over New Zealand around the same time the cyclone is developing.

WeatherWatch says it is that "powerful and protective" high pressure may control whether or not any tropical lows arrive here.

"The question may be more about what happens to New Zealand heading towards the end of the third week of December and start of the fourth week, leading into Christmas, as this big high moves away to the east.

"It looks as though this high over New Zealand may be the likely controlling factor for any tropical lows coming our way."