"Last week when we paid civil servants there was $217 [left] in government coffers," Biti told journalists in the capital Harare, claiming some of them had healthier bank balances than the state.
"The government finances are in paralysis state at the present moment. We are failing to meet our targets."
Zimbabwe's economy went into free-fall at the turn of the millennium, after President Robert Mugabe began seizing white-owned farms.
The move demolished investor confidence in the country, paralysed production, prompted international sanctions and scared off tourists.
After more than a decade - in which the country suffered hyper-inflation of 231 million percent and infrastructure that crumbled as quickly as prices went up - the situation is now more stable.
But public finances remain a mess and local business battles against unstable electricity supplies, lack of liquidity and high labour costs.
Zimbabwe's government has warned it does not have enough money to fund a constitutional referendum and elections expected this year.
Biti said that left no choice but to ask the donors for cash.
"We will be approaching the international community," he said.
The country's elections agency said it requires $104m to organise the vote.
Government's national budget for this year stands at $3.8bn and the economy is projected to grow 5%.
The mineral rich country is now using the US dollar and the South African rand.