Mr Karpal Singh, chairman of the Democratic Action Party, sparked an uproar when he claimed earlier this week that Sultan Azlan Shah, the titular head of northern Perak state, acted beyond his authority by interfering with the firing of a religious official.

Prime Minister Abdullah Ahmad Badawi said late on Thursday that police must investigate Mr Karpal for making comments that upset many people and were 'seditious and insulting' to the sultan.

Mr Karpal, a prominent lawyer and member of Parliament, denied being disrespectful to Sultan Azlan and insisted he would not retract his remarks.

'I stand by what I have said,' Mr Karpal said. 'What I've said is purely a legal matter.'

Mr Karpal claims Sultan Azlan had no right to recently reinstate a state religious department chief who was fired by an opposition alliance that wrested control of Perak and four other states in March general elections.

Malaysia's royalty consists of nine hereditary state sultans who perform ceremonial duties including appointing state chief ministers.

Several ruling party officials lodged police complaints over Mr Karpal's statement, which they claimed was seditious because it could stir contempt toward the royalty. Sedition is punishable by up to three years in prison in Malaysia.

'Karpal Singh has been rude to (the sultan). He intends to create a problem for citizens,' said Ms Hafizah Abu Bakar, a spokesman for Mr Abdullah's United Malays National Organisation party.

Police could not immediately be contacted on Friday. A representative of the Attorney General's office declined to comment.

Opposition activists have long called for Malaysia's sedition laws to be abolished, claiming the government uses them to suppress dissent.

Earlier this week, a well-known blogger, Raja Petra Raja Kamaruddin was charged with sedition for writing an article that implied the deputy prime minister was involved in a high-profile murder. He was freed on bail Friday after three days in police custody. -- AP