(AFP) - Zimbabwe's President Robert Mugabe on Monday stripped one of the top candidates to succeed him of a cabinet post, as the battle to replace the long-ruling leader intensifies.

Vice President Emmerson Mnangagwa, who also doubled as minister of justice, was replaced by ruling ZANU-PF party loyalist Happyton Bonyongwe. Mnangagwa will stay on as one of Mugabe's two vice presidents.

Mugabe, 93, has tried to enforce strict discipline in his ruling ZANU-PF party for decades and avoided naming a successor even as concerns have grown over his advanced age and failing health.

But the shake-up comes as infighting deepens in the ZANU-PF over who will take over from Mugabe, including allegations from Mnangagwa he was poisoned.

Mnangagwa's supporters allege he was struck down by poison-laced ice cream produced on a farm owned by first lady Grace Mugabe, who is also seen as harbouring ambitions to take over from her ageing husband.

Grace has publicly called on her husband to name a successor, ratcheting up tensions with Mnangagwa, a regime loyalist who has been widely tipped to succeed Mugabe.

But the open warfare between Grace and Mnangagwa has apparently left Mugabe furious.

Mugabe has repeatedly condemned factionalism within the party in thinly veiled rebukes to Mnangagwa and his wife's public posturing.

Mnangagwa's replacement as justice minister, Bonyongwe, is a retired army major general, who was the director general of the country's feared intelligence service.

Finance minister Patrick Chinamasa, who has been tasked with reviving the country's ailing economy, was replaced by Ignatius Chombo, who was home affairs minister.

Mnangagwa is one of the two ministers who were pushed out, while a total of ten others reshuffled, in a first shake-up since 2015.

Zimbabwe goes to the polls in 2018, and his party has endorsed him as its presidential candidate to face a coalition of opposition parties.

© Agence France-Presse