Deputy President Cyril Ramaphosa did not tell former police minister Nathi Mthethwa how to intervene in the 2012 Marikana strike, the Farlam Commission of Inquiry heard on Monday.

"I felt duty bound to try and help, to see the extent to which one could communicate to those in authority," Ramaphosa told the commission sitting in Pretoria.

He said he had had a phone conversation with Mthethwa on August 12, 2012. This was after he, then a nonexecutive director at Lonmin, had received an e-mail from Lonmin colleague, marketing director Albert Jamieson.

An extract of the e-mail read: "We need help. I urge you to please use your influence to bring this over to the necessary officials who have the necessary resources at their disposal."

Ramaphosa confirmed to the commission that he had received the e-mail.

"I just raised the concerns that Jamieson had raised. He had requested more police presence. I told the minister that they [Lonmin] needed help," said Ramaphosa.

"I felt that it was necessary to respond to the concerns raised in the e-mail, particularly in relation to the people who had been injured or killed," he said.

The commission, chaired by retired judge Ian Farlam, is investigating the deaths of 44 people during strike-related violence at Lonmin's platinum mining operations at Marikana, near Rustenburg in the North West, in August 2012.

Thirty-four people, mostly striking mineworkers, were shot dead in a clash with police, over 70 were wounded, and over 250 arrested on August 16, 2012. Police were apparently trying to disarm and disperse them.

In the preceding week, 10 people, including two policemen and the two Lonmin security guards, were killed.

Security was significantly heightened at the commission on Monday, ahead of Ramaphosa's testimony.

A police water canon, several Nyalas, and rolls of barbed wire, were stationed in the Tshwane council premises where the inquiry holds its public hearings.

Numerous police and presidential protection service vehicles were also at the venue. Some police vehicles were parked on Rabie Street outside.

The number of news crews had also swelled significantly, compared to previous days.

Dali Mpofu, for the wounded and arrested mineworkers, said during the public hearings in July that Ramaphosa used Mthethwa to exert political pressure on police to act against the protesting Marikana miners.

"You were the intermediary, the conduit, through which the pressure Mr Ramaphosa refers to was conveyed to the senior management of police and ultimately to the officers who killed people," Mpofu said while cross-examining Mthethwa at the inquiry at the time.