The restart of two nuclear reactors has been postponed as concern increases over radiation leaks from the Fukushima plant.
Southern Japan's Kyushu Electric Power Co had taken down two reactors for maintenance before the earthquake and they were due to be restarted in late March and early April.
However the electric utility has decided to postpone this due to safety concerns about radiation leaks coming from the Tokyo Electric Power Co's Fukushima Daiichi plant.
"We made this decision independently because the situation at the Fukushima plant has not yet stabilised," a company spokesman said.
"We're also aware that the government is considering tightening up safety measures."
Kyushu Electric is the second Japanese utility to announce a delay this week while engineers try to stabilise the Fukushima plant.
Chubu Electric Power Co , Japan's third-largest utility which serves the central Japan city of Nagoya, said it would delay the restart of its Hamaoka No.3 reactor by one week to carry out emergency response training.
It has also delayed construction of a planned No.6 reactor by one year
Kyushu Electric has not set a timetable for the restart of its Genkai 1,180-MW No.3 reactor and the 559-megawatt No.2 reactor, which were taken down in December and January respectively.
However the facility's two other reactors are operating normally.
The No.3 reactor in 2009 became Japan's first to use mixed-oxide fuel, or MOX fuel, which contains plutonium from recycled nuclear fuel.