Japan's government is considering extending its 60-year limit on the operation of nuclear power plants and may submit legislation on new rules next year, as it grapples with tight energy supplies and rising costs, the Nikkei daily reported on Friday.

The new regulations under consideration would remove limits on nuclear plant operation, allowing repeated extensions if approved by the Nuclear Regulation Authority, the newspaper said, citing a draft by the Ministry of Economy, Trade and Industry.

No comment was immediately available from the ministry.

Under current regulations, put in place after the 2011 Fukushima Daiichi nuclear disaster, a reactor can be operated for 40 years, followed by a 20-year extension if approved by regulators.

Four of Japan's 33 reactors available for commercial operation have been approved to operate up to 60 years.

Kyushu Electric Power Co Inc applied for an extension for two reactors at its Sendai nuclear plant on Wednesday, following similar requests by Kansai Electric Power Co Inc and Japan Atomic Power Company. 

As Japan faces a crunch in energy supplies due to the Ukraine conflict, as well as soaring energy costs, Japanese Prime Minister Fumio Kishida pledged in August to restart more idled nuclear plants and look at extending the lifespan of existing plants. 

The government aims to compile the new rules by year-end and submit relevant amendments to the law for approval by the regular parliamentary session next year, Nikkei said.