BANGKOK (AFP) - As lovers in Thailand prepare to shower each other with tokens of affection this Valentine's Day, the health authorities are urging couples to practise safe pandemic sex - including wearing masks during intercourse.

Daily coronavirus case numbers in the South-east Asian tourism hub have climbed from about 8,000 at the start of the month to almost double in the past fortnight.

The health authorities have expressed concerns this Feb 14 could exacerbate the trend, while acknowledging people have sex on other days too.

"Covid-19 isn't a sexually transmitted disease, but catching Covid-19 is possible through close-contact breathing and exchanging saliva," Bureau of Reproductive Health director Bunyarit Sukrat told AFP on Friday (Feb 11).

He recommended couples perform antigen tests before their date night to prevent passing on the virus to their partner.

Lovers are urged to "avoid face-to-face sex positions and deep kissing" and use contraceptives if they wish to avert unwanted pregnancies, he said.

"If possible, wearing face masks while having sex can help reduce Covid-19 risks," Dr Bunyarit said.

The holiday is popular across the kingdom and considered an auspicious day for couples to tie the knot.

There are often long queues at marriage registration offices, especially in the Bangkok district of Bang Rak, which translates to "love district" in the Thai language.