The Australian Federal Police has been investigating Australian mining firm OZ Minerals since September over claims it engaged in bribery in Cambodia in 2009, according to an annual report from the firm released on April 2.

The case relates to OZ Minerals’ former gold exploration venture at Okvau in Mondolkiri, where, in 2011, it is alleged the mining firm paid more than $1 million to three women on the board of its Cambodian joint-venture partner, Shin Ha, when it bought the company in 2009.

The women purportedly had highly placed relatives in the Ministry of Mines and Energy.

The payout was claimed to have been conditional on Shin Ha granting access to exploration licences from the ministry.

“The Australian Federal Police advised OZ Minerals in September 2014 that it is now conducting an investigation of OZ Minerals’ 2009 acquisition of the remaining holding in the Okvau joint venture in Cambodia in relation to foreign bribery claims,” the company’s annual report for 2014 reads.

Australian Federal Police originally dismissed a corruption case against the firm, but reopened the case in January 2013 after heated criticism from the Organisation for Economic Co-operation and Development for a lack of action on the case, among others.

The 21-month delay between the opening of the case and the direct investigation was attributable to preliminary investigations, the Australian newspaper reported.

In its annual report, OZ minerals said it did not take into account any potential repercussions from the bribing allegations in its financial results, concluding that “it is not probable that a present obligation exists” as of December 31, 2014.

“Unfortunately we are not in a position to comment on the AFP investigation or its processes,” the firm’s communications adviser Meaghan Wright wrote in an email yesterday.

The bribing allegations were first reported in 2011 by local media and have persisted after OZ Minerals sold its Okvau operation to Australian firm Renaissance Minerals for $18 million and stock options in 2012.

Craig Barker, exploration manager for Renaissance Minerals, said the Australian police had not reached out to Renaissance during its investigation.

Government officials at the Ministry of Mines and Energy and the Ministry of Interior said they were not aware of any Australian police effort to cooperate with the Cambodian government on the case.

“At the moment, the ministry is doing its best to reform the sector and improve the governance, and part of governance improvement is transparency”, Meng Saktheara, spokesperson for the Ministry of Mines and Energy, said yesterday.

But four years after allegations surfaced against OZ Minerals and five years after another Australian mining firm BHP Billiton was also accused of bribing the government, Transparency International executive director Preap Kol said the mining sector remains susceptible to corruption.

“The process of getting a mining licence is not yet transparent enough and does not encourage competitiveness among many mining companies,” Kol said.

“It is vulnerable to corruption and fails to adhere to best practice model and good governance principles.”