People in Tonga and Niue are being advised to bunker down and prepare for the worst from Cyclone Rene.

The storm has already brushed American Samoa, and is now moving southwest.

Forecasters expect it to hit Tonga in the next 24 to 48 hours.

At the Fiji Metservice, Latitate Waqaicelua says the cyclone is currently a category three, but is rapidly becoming more intense.

He says it will probably reach category four when it is right over Tonga, and he is expecting severe damage.

He says winds could reach 110 knots, with gusts of 160 knots.