Tropical Cyclone Vaianu is continuing to strengthen as it lies between Tonga and Fiji.
The Cyclone is centred around 300 kilometres west of the Vavau group.
It is moving slowly south west.
Marginal gale force winds, gusting up to 45 kilometres, an hour are expected to affected the Ha'apai group this morning.
There are also warnings of very rough to high seas and damaging heavy swells
Stong wind warnings are still in force for Vava'u and the Niuas.
Southern parts of Tonga could well be experiencing similar winds this afternoon.
At its centre Cyclone Vaianu has winds of over 110 kilometers an hour.
Forecasters say the cyclone is expected to change direction later and move to the south.