A prominent environmentalist who campaigned vigorously against an Australian-owned mineral sands mine in South Africa has been shot dead in his home, according to local media.

Sikhosiphi Rhadebe was a significant opponent of the Xolobeni mineral sands mine, owned by Perth-based company Mineral Commodities.

Mineral Commodities, through its South African subsidiary Transworld Energy & Minerals, plans to mine 2,900 hectares along South Africa's east coast.

Mr Rhadebe, nicknamed "Bazooka", was chairman of the Amadiba Crisis Committee which is opposed to the mine, claiming it is on ancestral land.

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Police told South Africa's Times Media Group that two men claiming to be police officers arrived at Mr Rhadebe's house in Mbizana to arrest him.

They did not say what they were there to arrest him for.

"As he was preparing to leave with the two men‚ they shot him eight times in the head outside his house," Police spokesman Captain Mlungisi Matidane reportedly said.

Activists say the mineral sands mine is on ancestral land. ( Mineral Commodities )

"He died on the spot ... and his wife and child have been hospitalised due to shock."

A statement from the Amadiba Crisis Committee said they would "not be intimidated into submission".

Mineral Commodities' executive chairman Mark Caruso said the company was "in no way implicated in any form whatsoever in this incident".

"Statements to the contrary are simply unfounded," Mr Caruso said in a statement to the ABC.

"The company is not in a position to comment with any authority on the incident.

"Despite our own internal enquiries, we are no further informed as to any of the specific facts surrounding this incident other than what has been reported.

"This company will not engage in any activity that incites violence ... [and] will cooperate fully with any investigations into this incident."