A senior member of South Africa's National Union of Mineworkers (NUM) has been shot dead in the platinum-belt town of Marikana, a union spokesman has said.

"He was killed last night. We don't know why at this stage but there appears to be a resurgence of violence in the area," said NUM spokesman Lesiba Seshoka.

The NUM has had tens of thousands of members in the platinum mines poached by the rival Association of Mineworkers and Construction Union.

The NUM has not released the name of the victim but mining firm Lonmin spokeswoman Sue Vey said he was the NUM chairman at the Roland shaft in the company's Western Platinum mine.

Union confederation Cosatu expressed shock and dismay at the murder.

"These killings continue even after a peace agreement facilitated by the deputy president of the country and all parties were involved," said Cosatu north-west secretary Solly Phetoe.

Cosatu believed that the killings were continuing because some organisations were reluctant to honour the peace accord, Mr Phetoe said.

"This shows they were never committed to bringing peace and stability in the area."

He called on President Jacob Zuma to declare a state of emergency at Marikana because workers were being "killed on a daily basis."

Cosatu sent its condolences to the man's family.

Police said he had been shot eight times. "The man was gunned down on yesterday night between 7pm and 8pm.

"He was on his way to visit his girlfriend when four men came out of the bushes and shot at his car," said Brigadier Thulani Ngubane.

He was hit once when he was driving and when he got out of the car the killers fired another seven bullets at him and he died at the scene.

North West Province Premier Thandi Modise condemned the "senseless" killing of union members.

"We call on police not to leave any stone unturned and appeal to communities to help with any information to ensure the perpetrators are brought to book," she said.