Prime Minister Abdullah Ahmad Badawi said today he was not worried by the return to politics of ex-deputy premier Anwar Ibrahim, who is campaigning in a critical by-election.

He also stood by his deputy Najib Razak, who is leading the campaign for the ruling coalition in the poll, and has faced allegations of links to the gruesome murder of a Mongolian woman and corruption involving arms purchases.

Marking a forceful return to politics, Anwar has mounted a campaign for the opposition Parti Keadilan Rakyat for the Selangor state seat of Ijok against the ruling Barisan Nasional coalition.

The weekend poll is seen as a litmus test of popularity for both sides ahead of a general election expected before 2009, but Abdullah said he was unconcerned by Anwar.

"I'm not worried," Abdullah told reporters, when asked about Anwar's return to the political stage.

"If people want him, he becomes popular, if people don't want him, he will not be popular. In politics that's what it is. I've been in politics a long time. I've faced him before," he said.

Anwar was sacked from his post in 1998 by then premier Dr Mahathir Mohamad and jailed over sodomy and corruption charges, a move which precipitated the opposition reformasi movement and gave birth to Keadilan.

He was freed in 2004 when the sodomy conviction was overturned, but the corruption charge remains.

The poll was called after a state lawmaker died earlier this month and campaigning has been fierce in semi-rural Ijok to win over 12,372 voters, with the contest marred by scuffles and slanging matches.

PM: I'm confident with Najib

Najib has been at the centre of the fight, with opposition parties alleging links with the sensational murder of the Mongolian model last year.

The model's lover, prominent political analyst Abdul Razak Baginda, has ties with Najib and is charged with abetting in the crime. Two police officers in an elite squad protecting Abdullah and Najib are accused of the murder.

However, Najib has vehemently denied knowing the woman, Altantuya Shaariibuu, or any involvement in the case.

Najib, who is also defence minister, has been linked to the payment of high commissions - amounting to more than half a billion ringgit - involving the purchase of submarines and fighter jets.

Abdullah today threw his full weight behind Najib.

"Najib does not have any links to the allegations they have made. I am confident with Najib as a deputy prime minister," Abdullah said.

"Those are attacks that should not be made by the opposition parties. They are personal attacks to win votes," he said.

Intense lobbying was continuing today, the last day for campaigning, amid a heavy police presence.

Out on the campaign trail, Anwar was mobbed by residents in the town of Batang Berjuntai in Ijok, who gathered to shake and kiss his hand and offer their support.

Lcal resident V Jeevan, 48, said he would be voting for PKR.

"I think there must be some change," he said. "Why not give them a chance. Then there will be more changes."

Anwar, however, was cautious on whether the support would translate into votes.

"If we can reach out to them and explain our positions, then we can win some votes," he said.

Fact boxes on Ijok