About 50,000 Victorians will be compensated with an “unprecedented” one-off payment following a blackout in extreme heat.

Residents who lost power for between three and 20 hours on January 28 will get an $80 bonus, while those who were in the dark for longer will receive up to $180 – the equivalent of three to seven months off their annual distribution charge.

Cheques will be mailed to about 50,000 people by the end of February and are separate to other claims for financial loss.

Power companies Powercor, CitiPower, United Energy, Ausnet Services and Jemena will compensate the customers as part of a $5 million package.

Premier Daniel Andrews said the payments were “unprecedented”.

“Under the rules that have been there for many, many years, well before we came to government, the payments would only be made to those who had lost power for say, 12 hours,” he told reporters on Sunday.

Heat and humidity on January 28 led to crippling pressure on the state’s distribution network.

The outage affected 95,000 businesses and households at its peak.

It was the highest-ever residential demand for a Sunday.

The Australian Energy Market Operator said the outages had nothing to do with supply, with air conditioners putting ‘enormous stress’ on the network.

The state government says it is working with the Australian energy market operator and industry to make sure supply needs are met during extreme weather.

Energy Minister Lily D’Ambrosio said the government recognised “how frustrating” blackouts are and affected customers deserved to be compensated.

“Network businesses will bear the full costs of this package and I’m pleased they’ve gone above and beyond the regulatory rules to support their customers,” she said in a statement.

Chief executives of the energy companies released a joint statement on Sunday announcing the package.

“We are sympathetic to people who lost power on that Sunday and importantly we recognise the inconvenience and discomfort this has caused our customers, particularly those who were without power for a sustained period of time,” the statement said.

“Our focus now is on working with government to identify and put in place sensible solutions – such as opt-in demand management – that prevents similar events on our networks in the future and do not drive up costs for our customers.”

The payments mean about 43,000 more customers will be compensated than under the Guaranteed Service Level, which only compensates customers who lose supply for at least 12 to 18 hours.

But David Southwick, the opposition’s energy spokesperson, claimed compensation for a power outage of up to 20 hours was no more than customers were already entitled to.

“It’s insulting after all of his big talk that Daniel Andrews has failed to guarantee Victorians any more than what they are entitled under the Guaranteed Service Level payments scheme,” Mr Southwick said in a statement.

“Compensation won’t help Victorians whose health is put at risk every time there’s a blackout. It won’t help families and businesses that may have lost thousands of dollars in perishable items of food and will now be forced to replace this at their own cost.”

Melbourne had a high of 38.1 degrees on January 28, according to Weatherzone.

Temperatures did not drop below 30 degrees in Melbourne until 4am, and remained above 30C in Mildura and the north-west.

-with AAP