Thai television flicked back to colour on Friday -- but with orders to keep it subdued -- as the government lifted a black-and-white rule imposed out of respect for the country's late king.

All channels, including international satellite networks, have been replaced with prepared state media programmes praising revered King Bhumibol Adulyadej's death, who died Thursday after a 70-year reign.

The monochrome order was initially set for 30 days.

But the government said Friday that broadcasters could resume their own programming by the end of the day, albeit with new mourning-period guidelines.

"Programmes or advertisements must not be aired to entertain," said a statement from broadcasting authorities.

Unacceptable content would include scenes of "dancing, celebrations and violence."

News presenters must also dress in black and white, which are both mourning colours in Thailand, and cannot "broaden, analyse, or criticise" information on any royal funeral ceremonies.

The latter directive does not change much in Thailand, where a harsh royal defamation law already blocks public criticism of the monarchy and has entrenched a culture of self-censorship across local and foreign press.

Thai dailies and new websites have been permitted to publish their own material over the past 24 hours, but they too have turned monochrome out of respect.

Bhumibol, who was 88 when he died, was worshipped with near-religious devotion by many in Thailand, where he was seen as the moral heart of a country riven by fractious politics.

The military government, which seized power two years ago, has also asked nightlife venues to "tone down" the party for the next 30 days as the nation grieves.

Bars and clubs in some of Bangkok's red-light districts swiftly closed shop after news of the king's passing.

A number of other upcoming concerts and events have also been cancelled, including this month's "Full Moon Party" -- an all-out bash on the southern Thai island of Pha Ngan that draws thousands of foreign tourists.