UPDATED 8.28pm: The Fijian government has declared a state of natural disaster as Winston sweeps in from the Pacific.

The latest development comes just after government imposed a total public curfew across the country as the monster category 5 tropical cyclone began to hit.

Meleti Bainimarama, Fiji’s natural disaster secretary, said the Government machinery will now roll into place to ensure the safety of members of the public, businesses, the economy and national assets.

Mr Bainimarama said the declaration will be in effect for the next 30 days.

Fijian Prime Minister Frank Bainimarama has today told his nation it's about to face a grievous ordeal.

MORE: Fiji flights cancelled as cyclone looms 

Mr Bainimarama's telling people to take the warnings seriously and pray.

He said Fiji must stick together and people must look after each other. 

Fiji's Land Transport Authority has ordered buses, minibuses and taxi operators to stop running.

Churches are also cancelling their services set down for tomorrow.

• Fiji flights cancelled as cyclone looms
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In the north, town and shopping centres have already closed.

New Zealander Ant Laity said about 65 boats have been evacuated from the marina and taken further inland.  

"People are just battening down the hatches in anticipation of some pretty serious winds."

Flights have been cancelled for holidaymakers heading to or returning from Fiji after Virgin Australia determined flying conditions were unsafe. The airline has suspended services between Nadi and Melbourne, Sydney and Brisbane today and tomorrow, and Monday's flights are under review. 

South Sea Cruises has cancelled sailings between islands until Tuesday, Fiji Times reported.

MetService meteorologist Lisa Murray said the centre of Cyclone Winston is situated between the country's two main islands.

"The eye of the storm is in between Viti Levu and Vanua Levu, halfway between the two of them but out towards the east of them," she said.

"So both islands, because the tropical cyclone is quite large, both those islands are going to be affected by the tropical cyclone."

The U-turn Winston took, which saw it turn after barreling though Tonga, and head towards Fiji, was not unusual, she said, despite some reports to the contrary.

"Actually western movements of TCs has been seen, especially in strong El Nino events, they can take westerly tracks," she said.

"What's happened here in the last 24 hours it's actually gone a few degrees further north than they were expecting, and it's moving a few kilometres faster than they were expecting. So rather than tomorrow, they're expecting it to impact Fiji today."