BANGKOK (BLOOMBERG) - Thailand is easing travel restrictions on visitors from 56 countries, including Singapore, Japan and the United States, ahead of the peak holiday season to boost the nation's ailing tourism sector.

Tourists are allowed to enter Thailand without prior visas but will need to carry a health certificate to prove they are free of Covid-19, and undergo a mandatory 14-day quarantine upon arrival, according to Mr Taweesilp Witsanuyotin, a spokesman for the Centre for Covid-19 Situation Administration.

Visitors will also undergo three virus tests while in quarantine, an increase from the two mandated earlier, Mr Taweesilp said.

More frequent tests for visitors during the quarantine might help the government shorten the isolation period to 10 days from next month, he added.

The quarantine will help the authorities prevent visitors from spreading the virus locally and is seen as a more effective strategy than limiting access to tourists from the so-called low-risk countries amid a fresh surge in cases worldwide, Mr Taweesilp said.

"The definition of which countries are low risk or high risk changes every day. So let's allow them all to enter, but put them into quarantines upon arrival," Mr Taweesilp said at a briefing on Thursday (Dec 17).

Travellers from the designated 56 countries, which also include Australia, Italy, and France, will be allowed to stay for up to 30 days for tourism activities as part of Thailand's unilateral agreements since before the pandemic.

Citizens from five countries - Argentina, Brazil, Chile, Peru and South Korea - can stay in Thailand for 90 days, according to the Covid-19 panel. But the country will not issue any visas-on-arrival, or allow 14 days free travel for those from Cambodia and Myanmar until the virus outbreak improves, it said.

"These are new processes and models for travel that we must adjust to in the new normal," Mr Taweesilp said.

Thailand is relaxing curbs on foreign tourists after a special long-term visa programme unveiled in September evoked lukewarm response and the authorities were forced to suspend a successful travel subsidy programme for local tourists to probe allegations of corruption.

Thailand is betting on a revival in its tourism industry to exit a recession, with the central bank forecasting it may take at least two years for South-east Asia's second-largest economy to return to pre-pandemic growth levels.

Foreign tourist arrivals generated more than US$60 billion (S$80 billion) in revenue from about 40 million visitors last year.