Former South African President Nelson Mandela remains in a critical condition in hospital, the government has said.

A statement from President Jacob Zuma's office on Tuesday said doctors were doing their best to ensure the "recovery, well-being and comfort" of the 94-year-old anti-apartheid icon, who was admitted to hospital more than two weeks ago with a lung infection.

"We must support him and support his family. We must demonstrate our love and appreciation for his leadership during the struggle for liberation and in our first few years of freedom and democracy by living out his legacy and promoting unity, non-racialism, non-sexism and prosperity in our country," Zuma said in a statement.

The statement came as Mandela's family members were meeting at his home in the village of Qunu.

His eldest daughter, Makaziwe, and some grandchildren were said to be at the meeting in Eastern Cape province, according to the BBC.