With prices skyrocketing and fuel shortages halting economic activity, Mnangagwa on Saturday night raised the price of fuel from $1.30 to almost $3.30, which puts the price of fuel in terms of the parallel market rate at about $1 per litre.
In a televised address on Saturday, President Mnangagwa said the fuel price hike would address the ongoing fuel problems, which have seen motorists queuing for hours at petrol stations.
"The ZCTU general council resolved to call for a nationwide stay-away with effect from midnight today following the insensitive and provocative increase of the fuel price by the president of Zimbabwe", the confederation, which represents people ranging from journalists to rail workers, said in a Twitter posting.
"So far the stay-away has been effective", Peter Mutasa, President of the Zimbabwe Congress of Trade Unions, said by phone. "Workers' salaries have been reduced to nothing and our suffering elevated to another level", it said.
Opposition Movement for Democratic Change (MDC) leader Nelson Chamisa said: "We have a national crisis which is descending into a humanitarian crisis".
Evan Mawarire, a cleric and activist who led anti-government protests in 2016 that shut down major cities, said: "You have cornered us and you leave us no choice. It's time to mobilise every person who truly loves Zimbabwe".
"Those in government may not admit it but they know in their hearts that they have failed", said Edmore Phiri, a tired-looking motorist who had just spent a second night in a petrol queue in Avondale suburb.
Mr Mnangagwa came to power in November 2017 after long-time ruler Robert Mugabe resigned following a military takeover and mass demonstrations.
Lil Uzi Vert says he's 'done with music'
Lil Uzi Vert announced on Instagram that he's "done with music ". "I WANNA WAKE UP IN 2013", read the post's message. In 2014, the Philadelphia rapper signed to Atlantic Records, having previously self-released two earlier projects.
"You can't have a country where people sleep in cars for days for a commodity that should be readily available".
The government says the prices were lower than in other countries in the region and that some foreigners were taking advantage, buying fuel in bulk in Zimbabwe for resale elsewhere.
The president's announcement came after fuel shortages which began in October a year ago worsened in recent weeks with motorists sometimes spending nights in fuel pump queues that stretch for kilometres.
When he took over from Mugabe, Mnangagwa pledged to revive the moribund economy and end the country's global isolation. The demand for fuel intensified this week with the start of the new school term this week.
Doctors in state hospitals went on a 40-day strike beginning early December demanding salaries be paid in USA dollars and improved work conditions.
Big companies in Zimbabwe, such as ABInBev's unit - Delta Corporation - which is owed about $120million (R1.6billion) in unremitted dividends, have hiked prices.
Mnangagwa, who leaves for a five-nation tour on Sunday, warned the government "will not allow" businesses to trigger a new round of price increases.
"Those designated fuel stations will be able to restock easily from the sales they make in United States dollars".