The operator of Japan's crippled Fukushima nuclear plant on Thursday logged a first-half net profit with its results boosted by a government bailout and electricity rate hike.

Tokyo Electric Power, the embattled utility at the centre of the worst nuclear accident in a generation, said it earned 616.1 billion yen ($6.27 billion) in the six months to September, reversing a year-earlier loss.

Sales climbed to 3.22 trillion yen, up from 2.88 trillion yen, owing to a government-approved electricity rate hike, it said.

The sprawling utility, known as TEPCO, was effectively nationalised last year with a huge injection of government money to keep it afloat as it faces massive compensation and clean-up costs after the 2011 nuclear disaster.

Reports this week said a ruling party panel was ready to recommend that the vast utility be split up as it faces increasing criticism over its handling of the atomic crisis.

A 9.0-magnitude tremor struck off Japan's northeast coast in March 2011, triggering monster waves that swamped the Fukushima plant's cooling systems, sparking reactor meltdowns and radiation leaks.

Tens of thousands of people were evacuated from around the plant with decommissioning of the site expected to take decades.