The suspension of the Test & Go no-quarantine programme for air travellers has been extended indefinitely, but three provinces will be added to the sandbox scheme.

The additional sandbox destinations are three islands in Surat Thani province - Koh Samui, Koh Tao and Koh Phangan - and the entire provinces of Krabi and Phangnga. No date was announced for its commencement.

Disease controls were also strengthened in 69 provinces, and the ban on nightlife continued.

The Centre for Covid-19 Situation Administration (CCSA)'s Taweesilp Visanuyothin said the CCSA agreed to prolong the suspension of the Test & Go one-quarantine-night-only entry programme until further notice, with Jan 15 the last date for all pre-approved arrivals.

About 10,000 people registered with the programme have not yet entered the country, he said.

The government had said earlier that all applicants must arrive in Thailand by Monday.

"Test & Go is a loophole for the virus to enter the country," Dr Taweesilp said.

Most new infections of the Omicron variant have been linked to people who entered under the Test & Go scheme, according Public Health Ministry officials.

There were 26,402 tourist arrivals in January, most of them through the Test & Go programme, according to CCSA figures up to Wednesday. Last year there were 416,160 foreign arrivals, most of them since Test & Go started on Nov 1 and before it was suspended on Dec 22.

Test & Go and the sandbox schemes for all destinations except Phuket were all put on hold on Dec 22, as the government tried to control a spike in coronavirus cases and the arrival of the Omicron variant.

The CCSA kept the status of the eight provinces approved for tourism promotion unchanged, meaning they are allowed to serve alcoholic drinks at restaurants until 9pm.

The provinces are:

•     Bangkok
•     Chon Buri
•     Kanchanaburi
•     Krabi
•     Nonthaburi
•     Pathum Thani
•     Phangnga
•     Phuket

Dr Taweesilp said the CCSA decide to step up public health controls in 69 other provinces. That included a ban on alcoholic drinks in restaurants.

The closure of all night entertainment - including pubs, bars and karaoke palours - across the country was extended. The CCSA had indicated they may be allowed to open in mid-January, the spokesman said.

The government advised that all offices continue the work-from-home format until the end of this month where possible, he added.