Forecasters are tracking the movement and intensification of Cyclone Tam over the Niuas and Vava'u island groups of Tonga.
Tam is lying west of Niuatoputapu, with wind speeds of up to 100 an hour expected this morning.
The cyclone is moving south-east towards Ha'apai and there are warnings of rough seas, and flooding including sea flooding of low-lying areas in Niuafo'ou and Niuatoputapu, Ha'apai and the Vava'u group.
For the rest of Tonga, there are warnings of rough seas, and flooding including sea flooding of low-lying areas.
The cyclone is expected to pass by Niue to the west, but forecasters say its outer rain bands are expected to sweep across the island.
