Two South African companies partnering a state-owned Zimbabwean mining company in a diamond mining venture in eastern Zimbabwe have been ordered to stop operations.

The Sunday Mail said Mbada Diamond Mining and Canadile Miners have been told to halt work by the country's environmental protection authorities.

The companies were found to have exploited the Marange diamond fields without having acquired an environmental impact clearance.

The fields have become the focus of international condemnation since Zimbabwean troops and police last year "brutally" evicted thousands of illegal diggers and panners.

Geologists say the field is one of the richest diamond areas in the world.

The Kimberley Process, the UN-founded body meant to stop the trade in blood diamonds fuelling violent conflict, reported in October that soldiers had murdered and tortured diggers, and that smuggling at Marange was rampant. The government illegally seized the field from a British company, African Consolidated Resources, in 2006.

In recent months the government has turned the claim over to Mbada, a joint venture between South African scrap metal dealer New Reclamation and Zimbabwe Mining Development Corporation.

Mbada is also in partnership with a little-known South African group, Core Mining, to form Canadile Miners.

The companies have been mining the area since September in violation of a court ruling that the claim belongs to ACR.

ACR is seeking an eviction order from the courts against Mbada and Canadile. The government said it wants to move the hundreds of villages living on the fields.

The environmental obstacle could stop the two entities' operations at Marange for months, with considerable loss of income to both.

By Staff reporter and agencies