Australia and the United States will continue to allow their citizens - thousands of them - to travel to Fiji amid the Pacific island nation recording its first cases of the Omicron variant of the coronavirus this week.

The Australians and Americans are arriving in droves to Fiji's Nadi International Airport - for many of them the trip has been postponed since March 2020 due to Covid-19.

Fiji had reopened its borders last month to returning citizens, diplomats and foreign nationals permitted to work in the country.

Last week, Fiji reopened to tourists with more than 2,000 arrivals at Nadi Airport in the first 48 hours.

Two Fijians returning from Nigeria on November 25 tested positive for the variant in a border quarantine facility.

The US has since upgraded its travel advisory on the Centers for Disease Control and Prevention website.

From December 6, all travellers to the US must provide proof of a negative Covid-19 test or documents showing their recovery from the deadly virus

The test must be taken no less than a day before arrival in the US.

The Omicron variant has been found in about 15 states, including California where flights have resumed to Fiji since the Pacific island nation reopened its borders on December 1.

Tony Greubel, of the US Embassy in Suva, said they are monitoring the situation there.

"Everyone is looking at the variant, so far seems like the vaccine is holding up well about it, symptoms have been mild and Fiji's population is largely vaccinated now.

"The Fiji government is determined that it's still safe to bring in tourists so as long as the public health science supports that we are all for bringing the tourists here and help the economy getting rebuilt."

More than 1,000 people have arrived in Fiji from the US since December 1, on flights from Los Angeles and Honolulu.

In addition to Americans, fully vaccinated travellers from New Zealand, Australia, the United Kingdom, United Arab Emirates, Canada, Qatar, Germany, Spain, France, South Korea, Singapore, Switzerland, Japan and most Pacific island countries and territories are now good to fly to Fiji.

Fiji is expecting close to 40 thousand visitors this month, with tourism officials confirming over 70,000 bookings received to the end of January.

"After almost two years of no tourism, we cannot wait to welcome back international travellers and greet them with our famous Fijian hospitality," said Fiji Airways Managing Director and CEO, Andre Viljoen.

"We have been working hard since March last year to prepare for this and ensure our guests have the safest and most enjoyable travel experience possible."

The World Health Organization has said those not fully vaccinated who are vulnerable to Covid-19, including over-60s, should delay travel to areas with community transmission.

It said more countries are imposing restrictions to combat the spread of the new Omicron variant.

The WHO said 'blanket bans' would not contain the strain of the virus which it previously warned presents a 'very high' risk globally.

Fiji's Government said it would not close the country's borders amid the first cases of Omicron.

Fiji health authorities are confident they have contained the Omicron cases.

"What we had done was that we pre-empted that there were countries that could generate a new variant. We pre-empted that and we made sure those countries have escalated pre-departure protocols," said Health Secretary James Fong.

Dr Fong said border health measures and surveillance will need to be strengthened and maintained.

The increasing number of Covid-19 cases in Europe and the emergence of the new variant, Omicron, are a cause for concern, Dr Fong said.

"We anticipate continued surveillance and testing in our communities and maritime islands to monitor and detect cases for early intervention."

Dr Fong said the two cases of Omicron from were Fijian citizens who had arrived on a Fiji Airways flight FJ1392 from Hong Kong on November 25 - the day the discovery of the Omicron variant was announced internationally.

He said both travellers tested negative for Covid-19 before departure from Fiji and before they left Nigeria.

"They entered a government-designated border quarantine facility immediately upon arrival into Fiji, tested positive while in quarantine, currently have no symptoms, and were fully vaccinated.

"With the exception of four passengers, all those on the flight were from non-travel partner countries, and therefore entered a border quarantine facility upon arrival to undergo the full quarantine protocol of 10 days. That has since been extended to 14 days."

New Zealand is yet to reopen its borders to international travellers but Australia has. Thousands of Australians have already arrived in Fiji since December 1.

Fiji is the number one holiday destination for Australians, with 40 percent of the total tourist arrivals from down under.

Australia has also reported cases of the Omicron variant, but the government said this will not affect re-opened international travel to Fiji.

More than 91 percent of Fiji's adult population are fully vaccinated, while close to 95 percent have received one dose of the Covid-19 vaccine.

Canberra's representative in Fiji, John Feakes, said Australians are travelling to Fiji because of its high vaccination rate.

"You'll see thousands of Australians will be coming in. You see the bookings are astronomical.

"I'm very confident that Australians will be spending time here, before Christmas, after Christmas and way into next year.

"We have a very strong demand right through to next year."

All travellers to Fiji will have to stay in a FijiCare hotel for three days and will be tested on day two. If they return a negative result for Covid-19, they will be released to the community. If they return a positive result they will be isolated for a further 10 days.

Those arriving from African countries will undergo a 14-day quarantine, including tests throughout their isolation.

Meanwhile, over 800 tourism operators in Fiji have completed Tourism Fiji's Care Fiji Commitment programme (CFC).

The programme ensures all services which tourists may encounter are fully compliant and well trained.

Tourism Fiji has launched a new global campaign via Saatchi & Saatchi NZ, announcing Fiji is officially 'Open for Happiness' with actress Rebel Wilson, who said she has fond memories of visiting Fiji as a child and was delighted to return as an adult to shoot the campaign.