BANGKOK (AFP) - With soldiers closing down Bangkok's notorious go-go bars and tourists forced to sneak sips of beer from paper cups, Thailand is dialling down its raucous party scene out of respect for the country's late monarch.

The passing this week of 88-year-old King Bhumibol Adulyadej has thrust the Buddhist nation into a period of profound mourning, with masses of tearful Thais filling the streets to pay respect to a king worshipped as an exemplar of moral virtue.

Like nearly all of their compatriots, Thai bar girls swapped their normally racy attire for more modest black dresses and shoes when they showed up to work on Friday (Oct 14) night.

In Bangkok's Soi Cowboy - a famed alleyway of luridly lit go-go bars and a barometer of the city's adherence to temperance during coups, street protests and religious days - patrons who trickled through were soon disappointed.

At around 10pm soldiers pulled the plug on the blinding neon lights as they enforced an early closing time in compliance with government orders to "tone down" celebrations as the nation grieves.

"Suddenly the army came. It was a group of five guys," said Mr Geroem Bonami, a 31-year-old tourist from Belgium.

"We were asked to pay and they started to tidy up everything and the girls disappeared."

Minutes after the ailing monarch's passing was announced on Thursday, Thailand's junta chief Prayut Chan-O-Cha took to national television to declare a one-year official mourning period.

He also asked the public to refrain from celebrations for at least 30 days, and dozens of events - from concerts to fun runs, wedding parties and religious festivals - have been cancelled since.

Television networks are also under orders not to broadcast any overly joyous images - such as dancing - with one major channel saying it would not be airing its roaringly popular soap opera series.

While the military regime has not issued an all-out ban on alcohol, which is common on Buddhist holidays, many shops have opted to stop selling drinks and bars around the capital are taking special measures to show that no one is having too much fun.

On the Khaosan road, a grubby centre for foreign tourists a stone's throw away from the King's palace, bars silenced the normally pounding music and served alcohol in paper cups instead of beer towers and buckets.

"There's no music tonight and no party because all the people are so sad. Everywhere in Bangkok, you cannot have loud music," explained Mr Ret Chhuon, a Thai barman, adding he was worried about an extended loss of custom.

"But we must do this because the king has died and we are so sad."

Foreign governments have urged their citizens to act respectfully as the kingdom mourns, while the Thai tourist authorities have asked travellers to dress in sombre and appropriate clothing.

Analysts have warned that any protracted clampdown on the party scene could drive visitors away and hurt the tourism sector - a crucial pillar of the kingdom's economy.

On the Khaosan Road some visitors said they were happy to keep it low-key, but would likely leave Thailand if the party didn't rev up again soon.

"If after a couple of days there are still no parties and alcohol, I might leave Thailand, said a 24-year-old Dutch tourist who only gave his name as Kaz.

Others were simply awed by the mass outpourings of grief.

"It hasn't put a downer on the holiday," said British tourist Callum Knight. "We got to see a part of history."