YAOUNDE (Reuters) - Cameroon opposition leaders accused President Paul Biya on Monday of preparing to steal the 2011 election in the central African state by seizing control of vote preparations from a specially created independent body.

Cameroon has been under pressure from Western donors and domestic critics to make its government more transparent, and a bill passed last week adds to a string of setbacks for democracy on a continent notorious for flawed or disputed votes.

"Paul Biya doesn't want change. He wants to die in power," Elizabeth Tamanjong, head of the main opposition Social Democratic Front (SDF), said of Biya, 77 in power since 1982.

"And the only way for this to happen (...) is by ensuring that there cannot be free, fair and transparent elections."

The ruling party-dominated parliament passed a bill on Friday giving the government oversight of poll preparations through the Ministry of Territorial Administration -- a task previously carried out by the independent electoral body ELECAM.

"This means that ELECAM is only a shadow organisation, no more an independent electoral authority," said Ben Muna, head of the opposition Alliance of Progressive Forces.

Biya, who set up ELECAM four years ago under pressure from Western donor nations threatening to cut aid, is expected to sign the bill into law within two weeks.

Analysts have said the risk of unrest in the oil-producing economy, the biggest in the region, could create problems for the government's policy agenda as discontent grows over persistent poverty and unemployment.

Once the bill is signed, MINAT will have the authority to appoint representatives to various commissions overseeing the full range of electoral preparations.

"This law is the worst law we've ever had because it brings back the administration and members of the judiciary into the electoral process in full force," said Afany Ngeh, executive president of the Foundation for Human Rights and Development.

"These are two very corrupt groups in this country that have paralysed elections in the past," he said.

Biya's Cameroon People's Democratic Movement (CPDM) introduced multi-party politics in 1991. But Biya and the CPDM have won every election since then and a constitutional ammendment in 2008 jetisoned presidential term limits.

Other setbacks to democracy in the region include a coup in Niger and violent protests over election delays in Ivory Coast.

"The bill is indicative of the bad faith of the government and shows the regime's determination to have total control over election matters in the country," said Mathias Eric Owona Nguini, a professor at Yaounde II University.

"The government ... wants to discourage the electorate and create an environment that favours voter apathy so that the ruling party will have its own way," he added.