Cyclone Vaianu, which has been bringing gale force winds to Tonga's main island, Tongatapu, today, is expected to intensify overnight.
Vaianu is around 180 kilometres to the west of the Tongan capital, Nuku'alofa, with winds at its centre due to strengthen to 65 knots or 120 kilometres an hour.
Bal Bir is a duty forecaster at the Fiji Met Service.
"Currently it is moving southerly at about six to ten knots but gradually curving south southeast in the next 24 hours. So it is following a southerly track at the moment and is further intensifying."
Once past Tongatapu there are no islands on the storm's current path.