Mnangagwa, who took over from ousted long-time ruler Robert Mugabe in November, has said he intends to tackle mass unemployment by luring back foreign investment and investing in infrastructure.
“It is a $4.5bn project and we are doing it in partnership with the Zambian government,” Monday’s state-owned Herald newspaper quoted Mnangagwa as saying.
“At our level as presidents, that is myself and (Zambian) President (Edgar) Lungu, we have agreed that the project must go ahead,” he said at a campaign rally on Saturday in the farming and mining town of Bindura.
The 1 600-megawatt project was expected to create 6 000 jobs, he said.
The proposal for the dam, 50km downstream of the Victoria Falls, was first mooted in the 1970s and revived by an engineering assessment in 2014.
Mnangagwa’s promise came just over a week after he commissioned the construction of a $1.5bn unit at Hwange Power Station in a joint venture between Zimbabwe and China’s Sinohydro.
Zimbabwe produces 1 200 megawatts of electricity, but relies on imports from neighbouring South Africa and Mozambique to meet its demand of 1 400 megawatts.
South Africa’s economy faces formidable challenges after Mugabe oversaw land seizures that saw agricultural output crash and the national currency abandoned after hyperinflation wiped out savings.
Millions fled abroad in search of work, while cash is strictly rationed by Zimbabwean banks.
Mnangagwa faces opposition Movement for Democratic Change (MDC) leader Nelson Chamisa in the presidential race.