Fears are growing in opposition circles in Zimbabwe that the ruling Zanu-PF party is making a new grab for power as it presses ahead with constitutional amendments aimed at giving parliament, rather than voters, the right to elect the president and to extend his term from five to seven years.

"This is a coup, a slow coup that is unfolding in Zimbabwe," veteran opposition politician and former finance minister Tendai Biti told the BBC.

But Zanu-PF, in power since independence in 1980, has vehemently defended the proposed changes.

"There's nothing that stops us from changing, to go to another system that's less costly, less controversial," party spokesman Patrick Chinamasa said.

The conflicting views highlight the deep polarisation that draft legislation - aimed at changing the constitution - has caused, pitting Zanu-PF and opposition supporters against each other.

This became clear during public hearings that parliament held recently to give people a chance to express their views on the proposed shake-up that will lead to:

• Presidential elections - held since 1990 - being scrapped
• Parliamentary and presidential terms being extended from five to seven years
• Parliamentary elections scheduled for 2028 being delayed to 2030
• President Emmerson Mnangagwa, whose second and final term is due to end in 2028, is expected to remain in office until 2030
• The new parliament will elect the next president.

"I support the bill in its entirety," a woman said at a public hearing in a sports arena in the capital, Harare, last week.

Thousands filled the venue, with speaker after speaker taking the microphone to echo calls for Mnangagwa to remain in office beyond 2028.

Mnangagwa took power in 2017 after ousting long-time ruler Robert Mugabe with the backing of military - and went on to win disputed elections in 2018 and 2023.

"Term limits must be extended from five to seven years and the MPs that we vote in, must be allowed to elect the president," a man said at the public hearing.

When the microphone was moved to the area where leading critics of the bill were sitting, there were scenes reminiscent of the violence and intimidation that has often marred Zimbabwean politics, with pushing, shoving and fighting - along with the snatching of mobile phones and journalists being ordered to delete videos of the chaos.

Leading opposition member and lawyer Fadzayi Mahere told the BBC that Zanu-PF supporters had caused the "commotion" in order to prevent critics from registering their disagreement with the bill.

Chinamasa denied that the ruling party's backers were behind the chaos.

"What reason do we have as Zanu-PF to be violent when the masses are behind us? The opposition does not accept that their view is failing to prevail," he told the BBC.

But the opposition says Zimbabwe is seeing a new wave of repression. In the run up to the hearings, the opposition groups say, the police banned more than a dozen of their meetings.

Opposition National Constitutional Assembly leader Lovemore Madhuku said he was beaten by masked assailants last month as the police watched.

Biti, who leads the Constitution Defenders Forum, is out on bail after being accused of holding a public meeting without official permission.

"We have a history of repression [in Zimbabwe]," Biti told the BBC.

Parliament is expected to pass the bill in the coming weeks, marking the culmination of a campaign that began in 2024, with the slogan "2030 - he (Mnangagwa) will still be the leader" being chanted.

The campaign faced some fierce detractors within Zanu-PF, but its main critic - Blessed Geza, also known as "Bombshell" - died earlier this year.

For supporters of the 83-year-old president, the political overhaul will entrench democracy, ending what they regard as toxic presidential election campaigns that often trigger violence and lead to disputed results.

"As you know, any election of the president - and it's not just Zimbabwe alone -. violence is associated with a popular vote," Chinamasa told the BBC, as he defended the proposed changes.

But for critics, the bill is a step towards recreating the "imperial presidency" they fought to end during Mugabe's 37-year rule.

A new constitution adopted in 2013 restricted a president to serving a maximum of two terms, further stating that any move to extend term limits would need to be endorsed by voters in a referendum - and, crucially, that a sitting president cannot benefit from any extension unless voters give their approval in a second referendum.

For the likes of Biti, the bill reverses these hard-fought gains, and could be challenged in the courts as, they argue, it violates the constitutional requirement that a referendum be held before the president's term is extended.

But Zanu-PF is confident that it is acting constitutionally, saying there is no need for a referendum as, in its view, the two-term limit remains - all that is happening is that a term will now be seven, rather than, five years.

But critics fear that Zanu-PF - led by Mnangagwa - could be moving stealthily to scrap term-limits.

"If they can get away with two years what stops them from getting away with 20 years?" Biti said.

Chinamasa dismissed suggestions that the bill signals a "dramatic shift" in how Zanu-PF will govern Zimbabwe.

"It's just that for this moment we would want to continue the political stability. We want to continue the economic development that is taking place since his excellency took over in 2018," Chinamasa said.

"When his time is up we will choose other leaders."

For the opposition, Zimbabwe is returning to its dark past.

"They are making the mistake that Mugabe made. That of closing [the democratic] space absolutely," Biti said.