The tiny oil-rich kingdom of Brunei instituted tougher Sharia penalties under Muslims law that drew criticism from Western countries, in 2014, then at the beginning of this year it issued a ban on "public celebrations of Christmas."

The fear that the Christian religious celebration will affect Brunei's main faith prompted the Sultan, Hassanal Bolkiah, to ban the public celebration of the birth of Jesus, the UK's Daily Mail newspaper reported.

Muslims caught celebrating Christmas, and non-Muslims found organizing celebrations, could face the lengthy prison sentence in Brunei which is a tiny corner on the island of Borneo in south-east Asia.

Non-Muslims are allowed to celebrate the holiday within their own communities, but they must not talk of their plans to Brunei's Muslims, who account for some 65 per cent of the 420,000-strong population.

"Using religious symbols like crosses, lighting candles, putting up Christmas trees, singing religious songs, sending Christmas greetings... are against Islamic faith," imams said in sermons published in the local press, AFP reported.

Punishment for violating the ban is five years in jail, and the government warned last year that Muslims would be committing an offence if they so much as wore "hats or clothes that resemble Santa Claus."

While Christians may celebrate Christmas, they have been told not to do so "excessively and openly."

Businesses were told to take decorations down and AFP reported authorities have stepped up spot checks across the capital.

NO CHRISTMAS DECORATIONS IN HOTELS

The hotels that are often used by Western tourists and business representative once flaunted lights and giant Christmas trees, but now they are bereft of festive symbols.

Around 20 per cent of Brunei's residents are non-Muslim, including substantial Buddhist and Christian communities.

"These enforcement measures are...intended to control the act of celebrating Christmas excessively and openly, which could damage the aqidah (beliefs) of the Muslim community,' said the Ministry of Religious Affairs in a statement.

Borneo prohibits spreading religion other than Islam to a Muslim, and doing so is a violation of the penal code.

"Some may think that it is a frivolous matter and should not be brought up as an issue," the imams are quoted as saying in the Borneo Bulletin. "'But as Muslims...we must keep it [following other religions' celebrations] away as it could affect our Islamic faith."

Some Brunei residents, however, risk the wrath of authorities by still celebrating Christmas and uploading pictures to social media as part of a #MyTreedom campaign supporting religious freedom.

"This will be the saddest Christmas ever for me," a Malaysian expatriate resident told AFP, requesting not to be named for fear of reprisals from authorities.

"The best part of Christmas day is waking up and having that feeling that it is Christmas, but there's just none of that here and you just feel deprived."

"All this is just because of what the Sultan wants. In 2013, I saw many Muslims together with Christians having a good time at their house parties. Everything was normal and good," he said.