Zimbabwe has ordered South Africa's Mbada Diamond Mining and Canadile Miners to stop work after they were found to have exploited Marange diamond fields without an environmental impact clearance.
Last year Zimbabwe banished thousands of illegal diggers and panners.
In 2006 Zimbabwe illegally captured the field from the UK's African Consolidated Resources (ACR).
Zimbabwe recently handed over the claim to the diamond field to Mbada, a joint venture between South African scrap metal dealer New Reclamation and Zimbabwe Mining Development Corporation.
Mbada has also partnered with Core Mining to establish Canadile Miners.
Since September both mining companies have been working in the area, a breach of a court ruling that ACR holds the claim.
ACR is currently pursuing an eviction order from the courts against Canadile and Mbada.
The Zimbabwean Government says it wants to shift the hundreds of villages located on the fields.
Both companies' operations at the fields could be halted for months because of the environmental obstacle.