The country's wholesale electricity prices hit unprecedented levels this month, highlighting a supply crunch not seen since the aftermath of the Fukushima nuclear crisis nearly a decade ago and sending power generators scrambling to source supplies.

Tokyo Gas, Japan's top city gas supplier and power retailer, on Thursday cut its recurring profit forecast for the year to March 31 by 15% to 68 billion yen ($652 million), blaming a 16.7 billion yen rise in its operating costs in power retail, largely because of the wholesale power market rally.

"We usually have enough power supply from our own plants, but we had to buy electricity this winter at very high prices, as peak-time demand soared also because more people stayed home amid the COVID-19 pandemic," Tokyo Gas CFO Koki Hayakawa told a news conference.

Hokuriku Electric Power also predicted a 79% fall in its annual recurring profit for the year to 5 billion yen as the record wholesale prices in January and December would likely trim its profit by 11 billion yen.

In contrast, Hokkaido Electric raised its annual recurring profit guidance by 50% to 30 billion yen, saying severe cold weather has boosted power demand and its electricity sales to other utilities, raising its profit by 11 billion yen.

Freezing temperatures across Asia have also driven liquefied natural gas (LNG) prices to record highs this month and pushed up the cost of shipping the fuel.

Hokkaido Electric saw no impact from the LNG market spike, saying it had sufficient inventory mainly through imports under long-term contracts, a company official said.

($1 = 104.3200 yen)

(Reporting by Yuka Obayashi; editing by Barbara Lewis)

By Yuka Obayashi