Fiji struggled Monday with devastating floods that have brought the country and its tourist industry to a standstill as authorities warned that conditions could worsen with a cyclone bearing down.

Cyclone Daphne is expected to compound the damage in the South Pacific nation, where a state of emergency is in force and flash floods have claimed at least three lives and forced 8,000 people to seek refuge in evacuation centres.

Fiji has "had a bashing", permanent secretary of information Sharon Smith Johns said, with water and power supplies cut in most areas, many roads closed and food supplies dwindling.

Thousands of tourists staying in Fiji's popular resorts were forced to contend with limited services as they waited for flood waters to recede enough to get to the airport, where they faced chaotic scenes.

"The information we've been given has been terrible. They say flights are on but you turn up and they've been cancelled," said Dorothy May Pechalaiya, whose flight back to London was delayed from Sunday until at least Tuesday.

"I had to sleep on a bench (at the airport) last night and I'm going to have to do it again tonight, and I'm disabled," she added, pointing to her walking stick.

"I'm really angry about the way we've been treated."

Davendra Singh said he had been forced to close his car rental business at Nadi airport, about two hours 30 minutes drive from Fiji's capital Suva, as he did not want vehicles wrecked in the dangerous driving conditions.

"This was supposed to be a busy week because we've got Easter coming up, lots of group bookings and tours. We've cancelled all that and have to see what happens with the cyclone now."

The Fiji Meteorological Service warned of an approaching cyclone and said more flooding on the main island of Viti Levu, where both Suva and Nadi are located, was expected.

It forecast "damaging gale-force winds" with gusts up to 110 kilometres (68 miles) per hour and "severe flooding of major rivers, streams and low-lying areas including sea flooding of low-lying coastal areas".

A government spokesman said the situation was worse than January floods in which 11 people died, with twice as much rainwater falling in half as much time.

However, late Monday the government lifted its embargo on airlines carrying people into the country, the national carrier Air Pacific advised. A number of empty planes have already flown in to ferry tourists out.

"This is very bad for Fiji, it will take a long time to fix up and get the tourists back," said Nadi taxi driver Mohammad Yakub.

He said his family was surviving on tinned food as all the crops in his small plot of land had been destroyed and his local market was unlikely to reopen for weeks.

Although Fiji has not called for international assistance, Australia and New Zealand said they were ready to help.

The regional powers have had a fractured relationship with Fiji since naval officer Voreque Bainimarama seized control in a 2006 military coup.

New Zealand Prime Minister John Key said they would work with non-government agencies rather than Bainimarama's regime.

"Typically what we've done in the past is give the resources to a non-government organisation on the ground we trust, say the Red Cross, rather than give it to the government to administer," he told Radio Live.

Australian Foreign Minister Bob Carr said Canberra was ready to provide up to Aus$1 million (US$1.04 million) to support disaster relief efforts while Qantas promised to put on extra services to help tourists leave.