Ontario has experienced higher-than-normal radiation levels stemming from a leak in a Japanese nuclear plant but not to levels that will affect human health, officials said on Tuesday.

Ontario Energy Minister Brad Duguid said there has been a "minor increase" in radiation levels in some parts of the province following the collapse of a Japanese nuclear plant.

Duguid confirmed the detection of elevated radiation levels to CTV Toronto's Paul Bliss, emphasizing that there was no danger to human health.

"It is not anywhere close to something that would be of any impact in terms of human health. It is not something that Ontario residents need to be overly concerned about," Duguid said on Tuesday.

"It is something that is always going to be monitored."

Information from the Canadian Nuclear Safety Commission and Health Canada, distributed by Duguid's office on Tuesday, said background radiation around the province remained normal but "minute levels of isotopes in the radiation have been attributed to the release in Japan."

The commission said the increase in radiation was so small that it was extremely difficult to measure against normal background radiation.

Ontario Environment Minister John Wilkinson said on Tuesday there was no problem with the province's drinking water, while Agriculture Minister Carol Mitchell said the Canada Food Inspection Agency would determine if there was any radiation in food or milk sold in the province.

Duncan Hawthorne, the president of Bruce Power, said that additional radiation monitors were installed in British Columbia after Japan's earthquake last month. The monitors started picked up increased radiation levels three weeks ago.

Higher radiation levels have also been detected in Little Rock, Ark., Philadelphia and other American cities. Radioactive iodine was recently discovered in milk in the eastern United States.

Duguid said he doesn't have details about the radiation increase, but has been informed about the increase by his federal counterparts. The federal government is in charge of monitoring radiation levels in air, water and food

Ontario's New Democrats said on Tuesday they could not believe the Ontario government knew so little about radiation levels in the province, one full month after Japan's nuclear disaster began.

"It's quite disconcerting," NDP Leader Andrea Horwath said. "The people of this province just want to know their water is safe, their food is safe, their milk, and it's quite surprising that we couldn't get the answers out of the government today."

To put the levels of radiation in Ontario into perspective, Health Canada said a five-hour airplane flight exposes a person to 50,000 times more radiation.

With files from CTV Toronto's Paul Bliss and The Canadian Press