The government said it wanted to ensure that the country's vast mineral wealth was used to benefit its people.

Many Congolese suspect that mining deals are often corrupt and campaign group Global Witness says the review was hit by a lack of transparency.

DR Congo has huge reserves of gold, diamonds, copper and more than a third of coltan, used in mobile phones.

Correspondents say these riches have been a key factor in the civil wars, instability and bad government the country has known since independence.

'Tragedy'

The enquiry into the mining deals have not been made public, sparking condemnation by Global Witness.

President Joseph Kabila won the country's first democratic elections in 40 years in 2006.

But his critics accuse him of agreeing deals with foreign mining companies which do not benefit local people.

Professor Peter Rosenblum from the US-based Carter Center, a consultant to the commission, said mining deals lie at the heart of DR Congo's problems.

"The tragedy of the many tragedies in the Congo was that the people woke up after years of war and found that the family wealth had been given away, or sold off, or at least as far as people knew, it seemed to have just flitted away."