The doctors, who earn a basic monthly salary of about US$385 before allowances, are also pressing the government to raise on-call allowances by 25 percent to $10 an hour paid in cash.
The southern African nation is short of U.S. dollars, the currency it adopted in 2009, causing price spikes and shortages of basic goods, medicines and fuel.
Mathabisi Bebhe, secretary general of the Zimbabwe Hospital Doctors Association which represents more than 1,000 members, said most junior doctors at the five major hospitals had downed tools to protest over pay, allowances and drugs' shortages.
More than half of public sector doctors joined the indefinite strike, he said.
With hospitals already short of drugs and reliant on patients to buy them, local pharmacies are no longer accepting insurance policies for purchases, instead demanding U.S. dollars in cash. When using bank cards, prices are at least three times higher.
"We are understaffed and underpaid and there are no medications in the hospitals," Bebhe said. "We are really hopeful that the government will intervene as early as possible. The duration of the industrial action depends on when the government gives a proper practical solution."
Health Minister Obadiah Moyo could not be reached for comment. The government has previously said doctors should present their grievances while at work and has relied on military doctors to help at state hospitals during strikes. At United Bulawayo Hospitals in the city of Bulawayo, senior doctors were only tending to emergency cases after closing the outpatient department, according to a notice to staff.
In March, the doctors went on strike and won an increase in pay and allowances, ending the first big labor dispute Mnangagwa faced since taking power.
But doctors were still struggling to survive, Bebhe said, after prices of basic goods rose by at least 300 percent since October. Annual inflation was 20.85 percent that month, the first time it has hit double digits in a decade.
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