It is unclear if former president Thabo Mbeki will attend the inauguration of the country's fourth democratically elected leader, Jacob Zuma.

The African National Congress president will be inaugurated at the Uion Buildings next weekend.

Several heads of state have confirmed they will be attending. However, US President Barack Obama?s name will not be on the guest list ? he has to attend to commitments he agreed to.

Minister in the Presidency Manto Tshabalala-Msimang on Wednesday said she could not say for sure if Mbeki would be there.

"Invitations have been extended to all the former presidents and deputy presidents. So it is expected that they will attend," said Tshabalala-Msimang.

Mbeki's office has been unavailable for comment.