SUVA (BLOOMBERG) - Flights to and from Fiji have been cancelled and a total public curfew put in place as a tropical cyclone with wind gusts of up to 325 kmh bears down on the South Pacific nation.

Prime Minister Voreqe Bainimarama said that Fiji was facing an assault of the "most grievous kind", as Tropical Cyclone Winston edged west across the archipelago. Residents across the country are required to stay indoors from 6pm local time, according to a government Facebook post, and all flights from Nadi International Airport have been cancelled.

The cyclone - which the Fiji Meteorological Service has classed a Category 5 on the five-step Australian scale - was located about 140km north-east of the capital, Suva, as of 3pm on Saturday.

Photos and videos posted on Twitter from the eastern island of Taveuni showed uprooted palm trees and telephone poles as well as houses with their roofs ripped off.

Virgin Australia Holdings and Fiji Airways cancelled all Fiji flights for Saturday and Sunday, and Qantas Airways, which code-shares with Solomon Airlines, scrapped flights to Honiara from Nadi, Fiji's main tourist hub.

Air New Zealand recommended on Friday that customers booked to travel to Fiji this weekend reconsider their plans.

The meteorological service warned of "very destructive" winds as the cyclone approaches Fiji's biggest islands of Vanua Levu and Viti Levu this evening local time.

Heavy sea swells and flooding was also expected along with average winds of 230 km an hour, according to a 4.17pm update on the service's website.

Winston initially passed west and south of Fiji before turning back toward the island nation earlier this week.