South Africa's special investigations police unit Friday said they are probing alleged irregularities at the state-owned oil firm PetroSA in connection with an oil deal with Ghana.
Paul Ramaloko, spokesman for the elite police unit known as the Hawks, refused to give details of the investigation.
A local paper, the Mail & Guardian reported Friday that the national oil company paid an extra $20 million for the acquisition of Sabre Oil and Gas Holdings Limited, which has acreage in Ghana's Jubilee oil field.
PetroSA admitted some improprieties had occurred as it fought to clinch the deal in its plans to expand in the oil and gas business in West Africa, noting it was "competing for these opportunities against many established players".
"In making transactions of the type that PetroSA has been involved in, swift decision making and quick turn-around times are critical and can sometimes mean a difference between closing a deal and losing out on an important opportunity.
"Therefore, in the process of increasing PetroSA's chances of successfully closing these deals, unfortunately some deviations from our normal procurement processes have occurred," it said in a statement.
The Hawks spokesman told AFP: "It's not long that we have started investigating PetroSA."
Ghana's Jubilee field, discovered in 2007 and one of the biggest finds in west Africa of the last decade, is believed to hold up to 1.8 billion barrels of reserves. Production started in 2010.