The tripartite alliance had to strengthen its bond beyond politics to become a family, President Jacob Zuma said on Sunday.

He was attending the funeral of David Thwani, the brother of Congress of South African Trade Unions (Cosatu) general secretary Zwelinzima Vavi, in the Eastern Cape.

About 1 000 people attended the ceremony at the Sada community hall, which is located in a small village between Whittlesea and Queenstown.

"He [Zuma] said when one of us is in pain, the entire family feels it and we want to be there to help each other," said ANC spokesman Zizi Kodwa.

Family bonds were important in the alliance, because "people needed to appreciate one another", Zuma told mourners.

The alliance - which consists of the ANC, Cosatu and the South African Communist Party - also needed to be concerned with issues affecting members' families.

Zuma said comradeship was about sharing grief and not just success.

The president was to have opened a University of Zululand campus in Richard's Bay on Sunday, but postponed his visit to attend the funeral.

It was a "historic" occasion for the people of Sada, said Kodwa.

"No president ever visited this village," he said.

On Saturday, Zuma spoke at the burial of the remains of murdered anti-apartheid activists the Pebco Three and Cosas Two, in Port Elizabeth.

Sipho Hashe, Champion Galela and Qaqawuli Golozi were leaders of the Port Elizabeth Black Civic Organisation, known as Pebco, when they were abducted, tortured and killed by security police in Cradock in 1985.

Zuma said their sacrifices would not be forgotten.

He was expected to fly back to Johannesburg on Sunday night to prepare for an ANC meeting early on Monday