Police Minister Bheki Cele says the fact that more than half a million South Africans were in the country's 243 prisons is a clear indication that immigrants are not worse than South Africans regarding crime.

He said figures indicated that only 18 000 of the 544 000 inmates in South African prisons were immigrants.

Cele spoke on Thursday at the Council of Mayors' conference being held at the East London International Convention Centre. The conference, which was organised by the South African Local Government Association (Salga), started on Thursday and will be wrapped up on Friday.

According to Cele, it is actually his countrymen and women who are involved in crime who give him sleepless nights.

Cele told the 200 conference delegates, "Foreign nationals are not a problem. It's South Africans. They are in prison in large numbers, which means they do things they are not supposed to do."

The minister, a former police commissioner, revealed that South African men raped 10 000 women over the three-month period between January and March this year.

He said 60% of the victims were raped in their own homes.

"They were raped where they are supposed to be safe by people who are supposed to keep them safe - their fathers, brothers, husbands, boyfriends, grandfathers, and their stepfathers," Cele told the horrified audience.

He said this meant that some sexual crimes were a family and societal matter, not a police matter.

"Yes, we come and arrest the rapist after committing the offence, but we can't be expected to hide under the bed to ensure you don't rape your daughter. Families must play their roles," he said.

He concluded his speech by urging all mayors to form good relationships with the station commanders of police stations in their areas and work together to keep South Africa safe.

President Cyril Ramaphosa delivered the keynote address at the opening session of the conference. The theme of the conference is "The role of mayors to enhance good governance and sustainability".

More than 100 of the 168 mayors in South African towns and cities are meeting in East London to deliberate and collaborate on matters concerning service delivery, local governance, and strengthening municipalities to carry out their constitutional mandate.