Tonga's National Disaster Office says tropical cyclone and storm conditions are expected for Vava'u and gale force winds for Niuatoputapu, Tafahi, and Ha'apai island groups.
Mafua Maka, from Tonga's National Disaster Office, says they are providing information to emergency committees in the affected villages.
"Low lying areas like Niuatoputapu, the low lying areas will be experiencing storm surge and flooding, so we'd advise them to move to a high area, or higher ground. Sometimes people prepare the usual 72 hours back, like for example an emergency kit."
Mafua Maka says the national and outer island emergency coordination centres have been activated.