The 264% rise affects two-thirds of the 7.8 million households using less than 90 kilowatts per month, while heavy consumers will pay around 80% more from Wednesday, official records show.
A consumer using less than 30 kilowatts per month will pay 28.50 rupees per kilowatt, compared to 7.85 rupees currently.
Large consumers billed at 45 rupees per kilowatt will now pay 80.55 rupees ($0.20).
The Ceylon Electricity Board (CEB) said the regulator had cleared it to make the steep increases from Wednesday, the first in nine years, to bail out its coffers with a $616 million deficit.
The CEB had asked for a larger tariff increase, of more than 800%, but the regulator capped it at 264%, officials said.
Sri Lanka, a country of 22 million people, is ravaged by a historic economic crisis, marked by severe shortages of food, fuel and medicine.
The island has also suffered daily power cuts for months, the CEB not having been able to buy the oil necessary for the operation of its thermal power stations.
The South Asian country defaulted on its $51 billion foreign debt in mid-April and is negotiating with the IMF for a possible bailout.
The restructuring of this debt is a precondition for the IMF's approval of a rescue plan.
© 2022 AFP