"We are in a defensive line -- we are not engaging."

South African soldiers in the Democratic Republic of Congo (DRC) have not been engaged in armed combat with rebels in the country, the SA National Defence Force said.

"I can confirm that... the DRC [defence] force engaged with the M23 rebels," SANDF spokesman Siphiwe Dlamini said.

"We are in a defensive line -- we are not engaging."

He said South African troops were in the DRC under the United Nations' Monusco peacekeeping mission.

However, a certain brigade comprising of soldiers from South Africa, Tanzania, and Malawi was mandated to engage "armed groups".

"They will not wait and watch while civilians are being attacked by armed groups," Dlamini said.

"They will intervene to engage, neutralise, and disarm."

President Jacob Zuma arrived in Luanda, Angola, on Thursday for consultations with Angolan President José Eduardo dos Santos and DRC President Joseph Kabila Kabange.

"The three heads of state are expected to discuss a range of issues relating to peace and stability in the region, particularly the current peace efforts in the DRC," Zuma's spokesman Mac Maharaj said in a statement.

On Thursday news agency Agence France-Presse reported that fresh fighting broke out outside the city of Goma.

M23 rebels attacked government-held positions on Wednesday night 20 kilometres north of the capital of North Kivu province.

Both sides said they were not yet able to say how many people had been killed or wounded.