After instituting tougher Sharia penalties that drew criticism from Western countries in 2014, Brunei has issued a ban on "public celebrations of Christmas."
Officials are said to be worried about Muslims adhering to non-Islamic traditions.
The country's Ministry of Religious Affairs said on January 8 that the ban was instituted for fear of Muslims being led "astray" by Christmas festivities, International Business Times reported.
The newspaper reported that last month, when local children and adults were seen wearing Santa Claus outfits, officials reacted by asking businesses to take down Christmas decorations.
But now the ministry has taken it to the level of an official ban on all such public festivities.
Such regulation raised fresh concern of religious restrictions after Brunei implemented a penal code last year that adhered closely to Sharia laws practiced in some Middle East countries.
Penalties in the new Brunei penal code include death by stoning and cutting off limbs.
A spokesman for the religious affairs ministry was asked by Agence France-Presse to comment, but shied away from a direct answer.
He, however, made reference to a ministry statement issued on December 27, which explained why the government put a ban on Christmas.
The ministry said any public act that commemorated non-Islamic festivities could be construed as "propagations of religions other than Islam."
"For example, in conjunction with Christmas celebrations, Muslim children, teenagers and adults can be seen wearing hats or clothes that resemble Santa Claus," a portion of the statement read.
"Believers of other religions that live under the rule of an Islamic country - according to Islam - may practice their religion or celebrate their religious festivities among their community, with the condition that the celebrations are not disclosed or displayed publicly to Muslims," it continued.
"Muslims should be careful not to follow celebrations such as these that are not in any way related to Islam... and could unknowingly damage the faith of Muslims."
Business establishments which likewise set a Christmas mood through store displays and decorations were also requested to take down their embellishments, according to the ministry.
The statement also said that businesses publicly displaying Christmas decorations were asked to take them down and had given their "full cooperation."
In April, Brunei's ruler Sultan Hassanal Bolkiah had announced he would proceed with implementing a new criminal code, which drew rare domestic and international criticism of the ruler.