IPOH: Two Malaysian political activists have been arrested ahead of a parliamentary showdown between the government and the opposition over control of a northern state, officials said Wednesday.

The Barisan Nasional coalition has deployed tight security in Ipoh, the state capital of Perak, to avert planned protests over its attempts to seize control of the state assembly which has been in limbo since February.

Mohamad Sabu, vice-president of the Islamic opposition party PAS who had been planning mass prayers in Ipoh, was arrested in Kuala Lumpur on Wednesday, said Tian Chua from Keadilan which leads the three-member opposition alliance.

"(The authorities) are just taking in anyone who can potentially pull crowds to the gathering," he told AFP.

Wong Chin Huat, a spokesman for BERSIH which campaigns for free and fair elections, was arrested for sedition late Tuesday after a press conference in which he advocated a campaign of civil disobedience.

"They arrested Wong under the sedition act and confiscated his laptop computer and handphone," his lawyer Edmond Bon told AFP.

Wong had urged the public to wear black to mark Thursday's session of the Perak assembly which is meeting for the first time since being plunged into crisis in February when defections cost the opposition its majority.

The sultan of Perak ordered the Pakatan Rakyat opposition alliance to step down in the state, which it won in general elections a year ago, but the chief minister has refused to cede power.

The coalition on Thursday needs to oust the parliamentary speaker -- an opposition appointee who has been blocking its attempts to exert its authority -- in order to regain control of the assembly.

Security was tight in the northern town of Ipoh, and police have said they will close down all the roads leading to the state assembly ahead of Thursday's session.

The Pakatan Rakyat parliamentary speaker, V. Sivakumar, appealed for calm and expressed optimism that the assembly would pass off peacefully.

"I really hope there is no fight tomorrow. There must be no violence. It's not going to be easy to handle, but all parties should be careful," he told AFP.