President Jacob Zuma has rejected the notion of South Africa lacking policy certainty and investor confidence.

"I think there is leadership in this country, very clear leadership. There is certainty on policy, there is certainty on economic policy. I would not accept the fact that there is no certainty," he told the National Assembly on Wednesday.

Zuma was responding to a question by Democratic Alliance parliamentary leader Lindiwe Mazibuko.

She said labour unrest had contributed to a "break-down in investor confidence", triggering warnings that South Africa's platinum could decline by 60% in coming years.

She asked where Zuma stood on the issue of strike balloting, and argued that ANC MPs had undermined government's efforts to improve the economy by removing a provision requiring a pre-strike vote from the Labour Relations Amendment Bill.

The president said labour strife at mines was a complex issue because of the emergence of rival trade unions, and it was vital that all roleplayers cooperate to resolve it.

"The difficulty has come in the manner in which the recent problems have emerged," he said.

He praised Deputy President Kgalema Motlanthe for his mediation efforts between unions and mining companies.

"I think they are working very closely to agree on the matters that have to be addressed in terms of addressing the problems at the mining level," he said.

Zuma said negative headlines were largely to blame on negative views expressed by the political opposition.

"Generally, people are saying we are doing very well. I have just come back from Japan. They are full of praises of South Africa... key investors. So it is not like a perception that is thrown around that investors are worried, not at all."

He said the economy was well-balanced and aimed at dealing with the country's specific challenges, including imbalances created by its apartheid past.

"Therefore, I confirm, the policies of the ruling party are absolutely correct, no-one could argue against them. Whoever argues against them does not understand the South African sentiment."