Weather: 'Even larger' cyclone roaring to life above New Zealand

The tropics are reaching peak activity with news an "even larger" cyclone will likely develop later this week.

In the Coral Sea, Tropical Cyclone Uesi has grown to a 'severe category 3' status as it moves towards New Caledonia, and it's expected to bring damaging winds, flooding rains and dangerous seas when it hits on Wednesday.

NIWA says it may track into the Tasman Sea this weekend, send a large plume of moisture against the South Island's West Coast early next week.

But forecasters warn an even bigger cyclone is roaring to life as a new low forms into a tropical storm north-east of Fiji.

This one will track southwards as it drifts down towards New Zealand, ending up off the east coast.

"The storm will become a 'severe' cyclone, being in more favourable conditions to grow than Uesi currently is in," WeatherWatch predicts. 

"This second cyclone will likely drift south over Tonga and lie northeast of NZ next week."

Fortunately a bubble of high pressure over New Zealand will act like a protective barrier and prevent a direct hit, however the cyclone is expected to impact on sea and beach conditions.