* Oil probe author says his team was ``compromised''
* Opposition say government tried to ``spoil'' report
* Transparency agency urges action on oil sector
ABUJA, Nov 5 (Reuters) - Nigerian President Goodluck Jonathan is coming under increasing pressure to tackle government corruption after an oil probe released last week showing billions of dollars of lost state revenues sparked a political row.
Reuters exclusively reported details on Oct. 24 of former anti-corruption chief Nuhu Ribadu's report on the oil sector, which showed Nigeria had lost tens of billions of dollars in cut-priced deals struck between government officials, the state-oil firm and multinational oil companies over the last decade.
It also found hundreds of millions of dollars of oil bonuses and royalties paid to government were missing.
Nigeria is one of the world's top crude oil exporters and a key supplier to the United States, China and India. It also holds the world's ninth largest gas reserves and one of its largest Liquefied Natural Gas export terminals.
The Ribadu committee report was presented to the Oil Minister Diezani Alison-Madueke, who commissioned the probe, in August but it was not made public or sent to the president. Once it had been leaked Jonathan requested it be given to him.
Alison-Madueke told Reuters the leaked independent report was a draft, it contained mistakes and the government needed to give input. Two members of Ribadu's committee were then quoted in local newspapers dismissing findings in the probe.
But when Ribadu presented the report to Jonathan on Friday the probe chairman said the report would not be changed and that the deriding committee members were ``compromised'' after being given top jobs at the Nigerian National Petroleum Corp (NNPC), the biggest stakeholder in the industry they were investigating.
``Even though the chairman (Ribadu) said that committee members became board member of NNPC, that does not disqualify them from being members of committee ... There is nothing wrong in any of them been appointed,'' Jonathan said in reaction.
But his political opponents disagree.
``Both men should have resigned ... the moment they were given the plum jobs (at NNPC),'' the Action Congress of Nigeria, a major opposition party, said in a statement on Sunday.
``The fact that they stayed on ... is the clearest indication yet that they were meant to play that exact role of spoilers.''
The Nigeria Extractive Industries Transparency Initiative (NEITI), part of the global EITI scheme aimed at improving transparency in commodity industries, added its voice to calls for government to take action and not bury graft reports.
``Had the remedial issues identified by the NEITI audit reports been dealt with ... some of the issues necessitating and identified by these probes would have since been dealt with,'' the agency said in a statement on Monday.
The agency found $9.8 billion of missing government revenue in its own audits of the oil sector for the period 1999-2008 and said there was ``no sufficient effort to recover the funds.''
Ribadu's probe was one of several set up after more than a week of nationwide strikes in January, which began as protests against the removal of petrol subsidies but morphed into a campaign against widespread corruption in the oil sector.
A parliamentary report in April found mismanagement and theft by top Nigerian officials involved in the corrupt fuel subsidy cost the country $6.8 billion.
Nigeria has arraigned some fuel marketers but has not taken action against government officials. Jonathan said the Ribadu report was not meant ``to investigate anybody in government.''
(Additional reporting and writing by Joe Brock; editing by James Jukwey)