President Emmerson Mnangagwa - who is trying to revive Zimbabwe's struggling economy - said the fuel price rise was aimed at tackling shortages caused by an increase in fuel use and "rampant" illegal trading.
Police fired teargas to contain unrest in several Harare suburbs and Zimbabwe's second city of Bulawayo, two days after Mnangagwa announced a massive fuel price hike in an effort to contain a runaway currency crunch.
Petrol prices rose from $1.24 a litre to $3.31 (2.89 euros), with diesel up from $1.36 a litre to $3.11 starting Sunday.
Simbai Rice, one of the demonstrators gathered in Harare, Jan. 14, 2019, says President Emmerson Mnangagwa's administration has failed to address increasing shortages of cash and basic food items.
"You can also expect that fuel will now mostly be available, but then it will be sold in US dollars".
However, the long lines of frustrated motorists illustrate the growing severity of a shortage of U.S. dollars, the currency Zimbabwe adopted after abandoning its own hyperinflation-ravaged Zimdollar in 2009, while everyday life is getting increasingly tough with rising prices of basic goods and erosion of salaries, which have remained static.
Mnangagwa took over from long-time ruler and autocrat Robert Mugabe following military intervention, before winning the presidency in a disputed July election.
Speaking during a working visit in Russian Federation on Monday, Mnangagwa said the increase "was necessary and still is".
Three people, including a police officer, were killed in Zimbabwe on Tuesday during protests against a sharp hike in fuel prices, police spokeswoman Charity Charamba said.
"We want Mnangagwa to know our displeasure in his failure", an angry Mthandazo Moyo in Bulawayo told news agency AFP.
"It's going to reduce demand for fuel because it's now a bit expensive and that will deal with speculative demand if it was there", said economist Godfrey Mugano.
He said the government has introduced new measures to curb a burgeoning parallel market in which fuel was being sold at five times the official price.
Mnangagwa also announced that foreigners will have to pay in foreign exchange for their fuel.
Government doctors went on a 40-day strike beginning in early December demanding salaries in United States dollars and improved working conditions, while teachers' unions called a strike this week for better pay but their calls went largely unheeded.
"We have the cheapest fuel in the world".
Hundreds of residents in the townships of Epworth, Mabvuku and Mbare, all opposition strongholds, protested by setting tyres alight and blocking roads with stones after the main labour union called for a three-day strike starting on Monday in response to the price increase.
Nelson Chamisa, who heads the opposition Movement for Democratic Change (MDC) said the situation was "descending into a humanitarian crisis".
He said more than 200 people have been arrested in connection with the violence.