After vigorously defending himself, Zuma bowed to pressure at the weekend and apologized - his second apology in recent years for similar acts.

Ruling African National Congress officials are due this week to commemorate the 20th anniversary of former president Nelson Mandela's release from prison at various ceremonies in the Western Cape, culminating in Zuma's state of the nation speech on the actual day Mandela was freed in 1990.

Resignation

Meanwhile, the opposition Congress of the People (COPE) has called for the resignation of the president to save the face of South Africa.

Mbhazima Shilowa, the deputy president of the COPE, said on Monday that the party would move for a motion of no confidence in President Zuma when Parliament resumed this week.

"We derive no pleasure from dealing with this matter. Ours is not about the humiliation of the president of the Republic," he told a media briefing after a meeting of the party's top brass at the weekend.

Shilowa said the motion would be called because of the impact of Zuma's behaviour on the country. The focus of the entire country was on Zuma due to his indiscretion when it should be on the issues that ordinary South Africans faced, such as unemployment, poverty and HIV/Aids.

Cope general secretary Charlotte Lobe said South Africa had become a "laughing stock" internationally because Zuma "failed to heed his own government's call on the pandemic".

She was referring to the HIV/Aids pandemic and said Zuma had not adhered to the government's programme on abstinence, being faithful and using condoms.

"His sexual advances to the children of his friends... go to the heart of his moral bankruptcy," said Lobe.

"President Jacob Zuma is not fit for office. He has tarnished the image of the Republic."