"The electoral term of the present government will come to an end on the 22nd of April. The time has come for us to work together again, to prepare for the fifth national general elections," Zuma said in a statement.
The ANC is expected to win the vote with a comfortable majority, although anger is mounting against the movement which spearheaded the fight against apartheid but now faces charges of failing to lift millions of blacks out of grinding poverty.
South Africans say many senior officials in the ANC, which won nearly two thirds of the vote in the last elections in 2009, have abused their government positions to line their personal pockets.
Angry residents in largely black townships across the country have over the past month, barricaded roads and set buildings and cars on fire in protests against poor services from the government, in power since the end of white minority rule in 1994.
Parties such as radical populist Julius Malema's Economic Freedom Fighters are tapping into the simmering discontent to advocate for nationalisation of mines and the seizure of white-owned land.