Zimbabwe's cabinet has approved draft legislation that would allow President Emmerson Mnangagwa, 83, to extend his stay in office until at least 2030.

Presidents would be chosen by MPs rather than in a direct vote and could serve a maximum of two seven-year terms, rather than the current five-year terms, under the proposals.

Justice Minister Ziyambi Ziyambi said public consultations would be held before the bill heads to parliament for debate, where both chambers are dominated by the ruling Zanu-PF party.

Legal challenges are likely as constitutional experts argue a referendum is needed if term limits are changed - and also point out that such amendments cannot benefit a sitting president.

Mnangagwa, who first came to power in 2017 after a military coup ousted long-time leader Robert Mugabe, won a presidential election the next year and a second term in 2023 - though the results were disputed.

Known as "the crocodile" because of his political cunning, his final five-year term is due to expire in 2028.

In a referendum held 13 years ago, Zimbabweans overwhelmingly voted for a new constitution that introduced presidential term limits when Mugabe's grip on power seemed entrenched - he had ruled the country since independence in 1980.

Hints that Mnangagwa, who was once Mugabe's deputy until they fell out over the growing political ambitions of the then-first lady, wanted to stay in power beyond 2028 started two years ago.

The slogan "2030 he will still be the leader" began to be chanted at Zanu-PF rallies with his supporters saying he needed to remain in office to complete his "Agenda 2030" development programme - though President Mnangagwa publicly rejected the idea.

He has faced some fierce detractors within Zanu-PF, but his main critic - Blessed Geza, also known as "Bombshell" - died last week.

This time last year Geza, a respected veteran of the 1970s war of independence and then member of Zanu-PF's powerful central committee, had launched a scathing attack on Mnangagwa's ambition to stay in power.

He apologised for helping him come into office and accused the president of nepotism in his bid to stay in office beyond 2028.

Zanu-PF expelled Geza from the party for disloyalty and he was forced into hiding.

Yet he continued to attract a large following on social media, where he regularly posted videos calling for protests.

Hours before his death a message posted on his social media pages urged Zimbabweans to carry forward the "noble war" to remove President Mnangagwa and "end the plunder of our country".

He was in South Africa when his family announced his death on Friday.

"At a time when silence would have been easier, he chose to speak out against corruption and nepotism that continue to undermine the promise of independence," Andrease Ethan Mathibela, national chairman of the influential Zimbabwe National Liberation War Veterans Association, said.

The government is now forging forward with its 2030 plans for Mnangagwa and says the intention behind the draft law is to strengthen governance and bring political stability.