The Central African Republic's post-coup government says it has suspended all mining agreements so officials can ensure companies have paid their taxes.
Rebels marched into the capital last month
Mining and Energy Minister Sylvain N'doutingai said the measure aimed "to fight against the mafia that is crippling the sector".
The suspension follows last week's announcement that the felling and sale of timber was to be halted to allow an inspection of companies.
Timber and diamonds are the CAR's main foreign currency earners but both industries have only ever made limited contributions to the national budget because of corruption.
The suspension will be lifted after every mining permit, as well as the fiscal situation of its holder, have been checked
mining and energy minister
Some companies may find they have to pay fines to the new regime for permit irregularities since the deposed President, Ange-Felix Patasse, personally issued licences almost universally.
The move will also bring into question a 99-year mining agreement the CAR signed in June giving Libya rights to all the country's natural resources which include diamonds, gold and uranium.
Mr N'doutingai - a nephew of the leader of the March coup, General Francois Bozize - said a joint commission would be set up to verify the legality of mining permits.
"The suspension will be lifted after every mining permit, as well as the fiscal situation of its holder, have been checked," he said in a national address.
Since March's coup, articles in the local newspapers have accused Mr Patasse and his family of reaping the profits from the country's mineral exploitation.
The daily independent newspaper Le Citoyen has published articles on Mr Patasse's Togolese brother-in-law Rene Koffi's diamond export business.
CAR is diamond rich
The paper accused him of "making US $1bn off the back of the Central African people" even as "public sector
workers were owed more than 30 months of back pay".
Mr Bozize reportedly estimated that CAR has lost "100 billion CFA francs (around $150m) every year through corruption" in the
mining sector alone.
World Bank doubts
Mr Bozize's take-over has been enthusiastically welcomed by central African nations but international institutions are waiting to see how the new government fares before re-starting loan programmes.
In Washington, there is doubt that Prime Minister Abel Goumba, 76, who has also taken on the economic and finance portfolio, will be up to the job of running the country's economy.
But Central Africans are mostly backing Mr Bozize, especially as he paid one-month's salary arrears to civil servants who have not been paid for two years.
Meanwhile, the former prime minister Martin Ziguele is still at the French embassy in Bangui - the new regime has so far not let him leave the country.