"We met as civil servants representatives and agreed to scale up our strike and engage in a stay-away from Monday to Friday next week," Tendai Chikowore, spokeswoman for the state employees' umbrella union told AFP.

The fresh call came after a one-day strike drew a lukewarm response, as most workers in the capital turned up at their stations on Thursday.

Chikowore said the workers want across-the-board pay rises including a raise from $200 to $538 a month for the lowest-paid government workers, medical insurance and an allowance for workers based in rural areas.

"We have had no response from the government," she said. "There is total silence and I am not sure they really understand the magnitude of the problem.

"We will be reviewing our strategy as we go. We urge the police not to harass our members. If that happens we are prepared even to go into the streets and fight running battles with the police."

Civil servants, particularly teachers, nurses and doctors, have been striking on and off for better salaries since 2007.

The situation came to a head in 2008, when staff shortages forced state hospitals to close some units and teacher strikes left only 50 days of classes in the whole year.

Zimbabwe's economy has begun recovering after a decade-long downturn, following a power-sharing agreement by long-time rivals President Robert Mugabe and Prime Minister Morgan Tsvangirai in the wake of failed 2008 polls.

But ghost workers are a problem throughout the civil service: about a third of government's 230 000 employees are not thought to actually exist, according to Finance Minister Tendai Biti.

So much of the current salary payments are being claimed fraudulently by people using fictional aliases.

Biti, a Tsvangirai ally, has insisted the cash-strapped government cannot afford to pay higher salaries.

Mugabe has accused the minister of deliberately sabotaging the government by refusing the increases.