Head of Nigeria's main anti-graft agency, Farida Waziri, says the immunity law, which suspends criminal cases against the president, vice president, state governors and their deputies while they are in office, is hampering the anti-corruption drive in one of the world's most tainted countries and should be abrogated. Gilbert da Costa in Abuja has this report for VOA.

Testifying at a senate committee hearing in Abuja, Economic and Financial Crimes chairman Farida Waziri, said immunity from prosecution has made elected top officials in Nigeria to become, as she put it, careless and reckless.

"I do not think we need that immunity clause because what is happening is our leaders, people that the people of this country queued in the rain and the sun to vote [for] them and they promised,' said Waziri. "And when they get there they totally forgot."

Civic groups in Nigeria say corruption in Nigeria remains a huge setback to fighting poverty and making government accountable.

Law enforcement officials estimate that about half of the country's entire budget is looted or wasted.

President Umaru Yar'Adua took power 16 months ago pledging zero tolerance for corruption.

But campaigners had complained that the government has been slow to arrest or investigate former president Olusegun Obasanjo, and some former governors accused of looting state funds.

Critics had repeatedly accused Mr. Yar'Adua of shielding the former leader from prosecution as a reward for his role in his emergence as president.  President Yar'Adua was Obasanjo's chosen successor.

A parliamentary panel, investigating why $16 billion of investment in the energy sector during Obasanjo's eight years in office failed to end power shortages, has indicted the former president.

A lobby group campaigning for a probe into the wealth amassed by Obasanjo during his time in office Wednesday submitted a petition to the anti-graft agency.

Debo Adeniran, spokesman of the group, says the petition was being presented the second time to the agency because the EFCC claimed it had no petitions against the former president.

"Last year, November 14, we came here to submit a petition against the immediate past president of Nigeria, Olusegun Obasanjo - that his activities while he was in power should be investigated," said Adeniran. "Up till this moment, the EFCC did not do anything."

During Obasanjo's presidency, the Economic and Financial Crimes Commission was accused of acting on his behalf, pursuing his enemies and turning a blind eye to corruption on the part of his cronies.