African National Congress (ANC) secretary-general Gwede Mantashe said on Wednesday that it was crucial that government and the public service unions finalise agreements on essential services, the SABC reported.

Mantashe was addressing a four-day national congress of the National Education, Health and Allied Workers' Union (Nehawu) in Ekurhuleni, east of Johannesburg.

Mantashe said that during his days as a mineworker, it was known that when they embarked on a strike, services like waterpumping, ventilation and shaft patrol would not be disrupted because they were essential.

During the recent three-week public sector strike, government argued that certain workers should not be on strike as they were considered essential services. However, the unions said that no agreement on what constituted essential services had been signed with government.

Mantashe's remarks came a day after Congress of South African Trade Unions (Cosatu) general secretary Zwelinzima Vavi criticised the ANC's national general council (NGC) for failure "to articulate a clear and systematic programme to lead society in a battle against corruption in the private sector, public sector and within the organisation".

Vavi also expressed disappointment about the NGC's resolution that the ANC was the "strategic political centre of power" in the tripartite alliance.

"It is a contradiction to say the ANC leads a revolutionary alliance, but the alliance led by the ANC is not a strategic political centre," he had said.