CAPE TOWN - Ailing former South African President Nelson Mandela continued to be responsive to treatment, the Presidency announced on Saturday.

Mandela's condition remains critical but stable, the Presidency said.

Mandela spent his 50th day in hospital where he is receiving treatment for a recurring lung infection.

"We appreciate that he (Mandela) has been in hospital for fifty days already, but we must take solace that he is being attended to by the most formidable and competent medical teams that we could put together, so he is under good care," presidential spokesperson Mac Maharaj said through the South African Broadcasting Corporation.

"He is responsive and we should take heart from that," Maharaj said.

Mandela was rushed to a Pretoria hospital on June 8. This is his fourth and longest hospital stay since December last year.