The Ontario government will need to learn from the nuclear crisis in Japan when building new power plants east of Toronto or deal with increased costs, a federal government-appointed review panel report released Thursday said.

The province is planning to build two new nuclear reactors at Ontario Power Generation's Darlington site in Clarington, Ont. It hopes the new plants will eventually produce about one-twelfth of the province's energy supply.

The panel said concerns stemming from the crisis at the Fukushima Daiichi nuclear plant in Japan, which began leaking radiation following a tsunami in March, are likely to result in the federal government adopting stiffer regulatory requirements.

Complying with any new requirements brought about by the crisis in Japan will lead to increased costs in building the plants, representatives from the province's crown corporation responsible for energy in the province, Ontario Power Generation, said during the hearings.

The province will have to foot the bill for the higher costs that would result if they have already signed a contract with someone to build the plants when those new regulations are introduced, the report said.

"The panel believes that it would be prudent for the government to ensure that lessons learned from Fukushima Daiichi nuclear accident and any resulting increased regulatory requirements are incorporated into the project as early as possible," the report reads.

The amount of money the province has allocated for the project has already gone up to $33 billion — $7 billion more than the original budget of $26 billion.

Any changes to regulatory requirements from the federal government would almost certainly force designers to make expensive changes, said Mark Winfield, a York University environmental studies professor and energy expert.

"They'll have to go back to the drawing board to some degree and redesign the system and then there will be the additional cost of then incorporating those design changes into the actual reactor," he said.

It will be difficult to say exactly how much the costs will jump until the regulatory changes are known, he said.

The Ontario government is not aware of any impending changes to regulatory requirements for nuclear plants, said Andrew Block, a spokesman for provincial Energy Minister Brad Duguid.

The province is nonetheless working independently to ensure all nuclear reactors in Ontario are safe, he said.

"This is something that's been dealt with since the Fukushima incident happened," he said.

"Incorporating any safety mechanisms that comes out of the review of that has always been our top priority."

A spokeswoman for the Canadian Nuclear Safety Commission, the federal department responsible for nuclear safety regulations, says it has appointed a committee to review its safety practices in the wake of the Japan nuclear crisis.

However, she said they are not committing to make any regulatory changes at the moment.

They've already taken steps to review the safety of Canada's nuclear plants in the wake of Japan's nuclear crisis.

The commission asked OPG to review the safety of its nuclear reactors in the weeks following the leak in Japan. The agency concluded all the plants were safe and robustly designed in a report released in April.

It's very likely the federal government will be introducing some kind of changes, said Winfield.

Ontario Power Generation is keeping the possibility that new regulatory requirements will be coming in mind as they proceed with the project, a spokesman said.

"A lot of lessons from Fukushima are not completely understood yet," said Ted Gruetzner, manager of media relations at OPG.

"You would take what we have learned on our operating basis right now ... and then whatever lessons that you learn as you go forward you would incorporate those as you build the plant."

The panel's report concluded the project contained no major environmental risk and recommended the project be approved.

The move follows ongoing protests from environmentalists about the safety of the project.

Greenpeace protesters interrupted part of the panel's 17-day public hearing in March and April.

The hearings went ahead despite the environmentalists' concerns that the panel was ignoring safety questions raised by leaks at the Fukushima plant following the tsunami.

Including a discussion of the crisis at Fukushima as part of the hearings would have made it easier for the province to incorporate any safety changes that would result, said Greenpeace's Shawn-Patrick Stensil.

"This panel could have looked at those issues and made recommendations on how safety could be addressed," he said.

The federal Minister of the Environment and the president of the Canadian Nuclear Safety Commission appointed the independent panel to look at the potential environmental effects of the proposed project.

The panel has submitted the report to the federal Minister of the Environment. He will discuss the matter with the federal cabinet and it will be responsible for deciding whether or not government departments can start issuing licences for the project.

The provincial NDP has previously promised to abolish the plan to build the nuclear reactors altogether and instead invest $1 billion so residents of the province can retrofit their homes.

The Progressive Conservatives say they would go ahead with the government's plans to expand nuclear power if they are elected this October.