JOHANNESBURG (Reuters) - South Africa is likely to hold a parliamentary election in May next year, after the electoral commission announced a timeline on Wednesday, in a vote that will decide whether President Cyril Ramaphosa remains in power.

The commission said the election would take place sometime between May 7 and August 5 next year but Ramaphosa, who has the final say on the date, has previously said he wants the vote before the end of May.

Voters will elect 400 members of the national assembly by proportional representation. The president is elected by the national assembly after the vote.

The provincial legislature and premiers of each of South Africa’s nine provinces will also be elected.

The ruling African National Congress (ANC) has won every election since sweeping to power under the leadership of Nelson Mandela at the end of apartheid in 1994, although its majority has steadily declined.

Most analysts expect the ANC to retain its majority next year but the size of any victory would dictate Ramaphosa’s ability to continue his economic and investment drive considering the deep rifts in the party.