State departments owe $20m to the Zimbabwe Electricity Supply Authority (Zesa), and prepaid meters are being installed so they can only use the electricity they have already paid for.
"It's already under way but I cannot project when we will be done," said Zesa spokesperson Fullard Gwasira.
Energy minister Fortune Chasi said the 600,000 meters would be "good for budgetary control".
Chasi had to intervene recently to ensure the Treasury paid $10m of Zimbabwe's $33m-plus debt to South African electricity utility Eskom.
The minister also threatened to switch off non-payers. "Zesa has a legal obligation to cut its losses. It cannot continue to supply power to people who do not pay," he said.
"Switching off non-paying consumers is a real option. Be warned. This is regardless of who you are."
Zesa is owed $1.2bn, including $350m by local authorities and $200m by mines. It says it needs revenue of $15m a month to keep the lights on.
The country has only 55% of the electricity it needs after SA and Mozambique restricted supplies due to outstanding debts, which have been reduced to $75m.
This has triggered massive load-shedding, with consumers sometimes going for 17 hours a day without power.
Like most parastatals, the power utility suffered losses during the Robert Mugabe presidency, when Zanu-PF bigwigs were shielded from settling bills.
Mugabe owed Zesa more than $345,000, and local government minister July Moyo was recently dragged to court over a $414,775 bill.
Industry has warned that load-shedding in the productive sector will be catastrophic for the underperforming economy and employment.
"It will impact on forex availability because you can't talk of an industry to generate forex when there is no electricity to support it," said Zimbabwe National Chamber of Commerce CEO Chris Mugaga.
"Also, the ease of doing business is compromised . no-one will want to invest in an economy where it is dark."
Would you like to comment on this article?
Sign up (it's quick and free) or sign in now.
Please read our Comment Policy before commenting.