Soldiers are to be deployed, instead of police, to patrol and protect South Africa's borders, government spokesperson Themba Maseko said on Wednesday.

Members of the South African National Defence Force (SANDF) would be better placed to fight cross-border crime, such as cars being smuggled to neighbouring countries after they were stolen in South Africa.

Maseko told a post-Cabinet briefing, soldiers would gradually replace the police both along the country's frontiers and at border posts.

"There will be an intermediate phase where some parts will be guarded by police and some parts guarded by the SANDF," he said.

"Eventually the task must be given to the SANDF but in the meanwhile it will be shared."

Cabinet has yet to decide how many soldiers will be needed and when their deployment will start.

The announcement marks a policy reversal.

Police began taking over responsibility from the army for border security five years ago but the move has been widely regarded as a mistake.