Anwar Ibrahim said today he would return to political life full-time from next month after working as an academic since his release from jail.

The former deputy premier has been a thorn in the government's side since 2004 when a sodomy conviction against him was overturned, regularly lobbing salvos against the ruling coalition of which he was once a leading member.

"I believe it is a challenging task," Anwar told reporters ahead of his permanent return to Malaysia after a year overseas as an academic and on the international lecture circuit.

"I am not of the view that it is going to be plain sailing, I know the problem of the system here, how it operates," he said, citing government surveillance and local media censorship of opposition politicians.

His aides said that his reinvigorated political career will start from May and that they had begun the search for an office from which he is expected to launch campaigns, devise strategies and hold press conferences.

Anwar, 58, was sacked as deputy prime minister in 1998 by then-premier Mahathir Mohamad and jailed after convictions for sodomy and corruption involving the misuse of power.

Reform agenda

The corruption conviction still stands, meaning he is barred from running for office until 2008 - the same year national elections are to be held.

"We are talking about a reform agenda. Now the fact that I'm not a member of Parliament ... or the fact that I can't contest before 2008 is something we have to deal with. And Malaysians know that," he said.

Anwar said he would focus on building up the opposition party Parti Keadilan Rakyat (PKR) led by his wife Dr Wan Azizah Wan Ismail, and shoring up links with other opposition parties.

"I think PKR and me personally should be able to forge that sort of understanding separately with those parties," he said.

Anwar said that in order to fund his political activities he had sold his large bungalow in a upmarket part of Kuala Lumpur popular with ministers and government servants, and would move to more modest accommodation.