Zimbabwe-focused diamond miner African Consolidated Resources Plc (ACR) has been charged with fraud and violating Harare's precious stones laws, an ACR press release said.

In the statement, quoted by various media sources, ACR said it was now facing allegations of unlawfully acquiring diamond claims in the controversial Marange diamond field, by using unregistered subsidiaries – a process authorities consider fraudulent.

"ACR has been legally advised that this should make no difference to the validity of the Marange Claims and accordingly that the charges are groundless," the diamond miner said.

London-listed ACR is already involved in a court battle with the Zimbabwean government which revoked the miner's title in Marange in 2006.

Harare's high court confirmed ACR's titles in a September 2009 ruling, but the decision was rescinded in mid 2010, citing "irregularities in the acquisition and registration of claims."

Last week, Zimbabwe police arrested six directors – five officials from the state-owned Zimbabwe Mining Development Corporation (ZMDC) and a Zimbabwean representative of its South African partner, Core Mining and Minerals – linked to a joint venture firm mining diamonds in Marange, also on allegations of fraudulently acquiring the concession.

A magistrate will rule on Tuesday on the executives' bail application.