Warnings for Tonga with ’good chance’ of cyclone forming

The storm was expected to be a cyclone by the team it crossed Tonga's main islands on Sunday. - Photo: Tonga Meteorological Service

Forecasters in Tonga say there's a "good chance" a tropical depression heading towards the country will become a cyclone tonight.

The Meteorological Service said the system is intensifying and heading southwest towards the populated islands of Vava'u, Ha'apai and the main island, Tongatapu.

It comes less than 24-hours after another depression brought damaging swells and flooding to several islands.

The Meteorological Service director, Ofa Fa'anunu, said the country is in for a rough weekend.

"There's a high chance for a lot of heavy rain and flooding, as well as some damaging swells that could be expected as it moves south tonight," he said.

"We expect it to be very close to the islands of Vava'u, Ha'apai and even the main island of Tongatapu in the next 12 to 24 hours."

It's a year since Cyclone Gita killed two people and caused extensive damage in Tonga.