Japan's nuclear watchdog Tuesday denied claims the country is planning to restart six reactors, just days before the second anniversary of the quake-tsunami disaster and nuclear crisis at Fukushima.

"Nothing has been decided as it's impossible for us to predict how many reactors can reopen this year before new safety measures are announced," an official with Japan's Nuclear Regulation Authority told AFP.

"Even if some reactors clear our safety screening, there will be additional procedures ahead, including getting the approval of local residents."

On Monday, the head of French nuclear group Areva, a major supplier to Japan, said half a dozen reactors would reopen before the end of the year and that most of the country's nuclear plants would eventually come back online.

"We think that there could be a half dozen reactors that will restart by the end of the year," Areva's Luc Oursel told a new briefing Monday, basing the projection on expectations tied to new regulatory rules expected in July.

Japan switched off its atomic reactors for safety checks in the wake of the March 11, 2011 disaster that saw a wall of water hit the Fukushima plant, crippling its cooling systems and sending reactors into meltdown.

Radiation spread over a wide area forcing the evacuation of tens of thousands from their homes, possibly forever.

Only two of Japan's 50 reactors are operating as anti-nuclear sentiment runs high across the nation.

Japanese Prime Minister Shinzo Abe reiterated on Tuesday that he would only allow reactor restarts if their safety could be ensured.

"There won't be any resumption of nuclear power plants without safety approval," Abe told parliament.

"But if their safety can be confirmed, we will respect that decision and proceed with resumption."