This disappearance of billions of dollars (euros) from public purses was "abetted" by a culture of secrecy within oil and mining multinationals about revenues paid to governments, Global Witness said in an investigation.

The result was entrenched poverty and political instability, the group said, demanding new rules which would compel both companies and governments to be more transparent about payments.

"These scandals could not have happened if companies had been obliged to publish their payments to governments, and governments to publish their earnings," Global Witness campaigner Gavin Hayman said.

"But leading countries and companies are doing next to nothing, and revenues that should be used to reduce poverty go on being misused or wasted."

Global Witness campaigns about the misuse of natural resources, and is best known for its efforts to end the trade in so-called "blood diamonds" mined from conflict zones.

The group's latest report, called "Time for Transparency", uses the examples of five mineral-rich countries: the West African nations of Angola, Congo and Equatorial Guinea, Kazakhstan in Central Asia and the tiny Pacific island of Nauru.

In Kazakhstan, the regime of President Nursultan Nazarbayev faces accusations of massive corruption involving oil revenues, including a billion dollars (810 million euros) placed in an offshore bank account, the report said.

The activities of French firm Elf, which is now part of French giant Total, in Congo already form part of a massive corruption scandal and court case involving the oil group.

However this "legacy of opacity and hair-raising accounting" remains in the poverty-stricken nation, depriving its people of vast amounts in revenues, Global Witness said.

Perhaps the most dramatic example comes in Nauru, the tiny and isolated island state which briefly became the richest nation on the globe per head of population due to its massive reserves of phosphates.

This money was squandered by corrupt officials and crooked behaviour, the report said, leaving the island a "wasteland" now largely synonymous with money-laundering scams.

"Bankrupt, in social and political turmoil, and facing possible extinction from rising seawaters, Nauru is a sinking ship," Global Witness noted.

The answer to these problems was simple, the group said.

"The major finding of this report is that none of the revenue embezzlement scandals discussed herein could have happened if multinational companies had been required to disclose publicly their basic payments for resources to the state," it said.

The British government had done some "valuable work" in trying to tackle the transparency issue, but controls remained voluntary and were thus of limited use.

"The report calls instead for companies to be made to disclose their payments to states via laws, stock market rules and accounting standards," it said.

"This would cost little, protect companies reputations and create fairer competition."

TERRA.WIRE