Firm action will be taken against those who mock the royal command that ‘Allah’ is exclusively for the use of Muslims, a federal minister has warned.

Rural and Regional Development Minister Shafie Apdal (left) said anyone issuing provocative statements would be violating the constitution, which places Islam as the official religion of the federation.

"Don't take this lightly because the ... Agong is a sovereign institution for the Malays, what more since his royal highness has issued a command about Islam. Therefore, this must not be belittled by any party," he was quoted as saying in Sinar Harian today.

Last Sunday, Kedah Sultan Abdul Halim Mu'adzam Shah had said - in a statement read out by a representative at a ceremony - that the word 'Allah' is exclusively for Muslims. The sultan is also noted as the Agong.

Sarawak PKR chief Baru Bian has since said that the ruler may have been ill-advised.

He argued that, since there are no royal houses in Sabah and Sarawak, the Agong should not have jurisdiction over non-Muslims on the matter of religion.