Six new forest fires ignited in Ontario on Tuesday, while current blazes forced the evacuation of another community and disrupted rail service.

The blazes, which have been raging since Saturday are costing the Ontario government $2 million a day, the Ministry of Natural Resources says.

Arid conditions combined with high temperatures and unpredictable winds have ignited at least 50 fires that have cut a swath through a large part of northwestern Ontario. More than 800 people have been evacuated from their homes, and are not expected to be allowed back anytime soon.

Lightning strikes and shifting winds are fanning the flames, say fire management specialists.

"One fire is influencing the behaviour of others," Wendy LeClair, communications officer for the emergency response team of the Wawa Fire District, said Tuesday.

"These fires are still pretty hot and when the weather changes we expect Fire 13 to fluff up and get rolling again."

Fire 13 is the largest of three fires burning in the Wawa district at 45 kilometres long. The massive blaze is throwing out spot fires as well.

On Tuesday, smoke from Fire 13 forced the evacuation of the community of Hillsport.

Burning just five kilometres from a Canadian National rail line, it has also caused periodic closures of the tracks.

"We're still running trains," said CN spokesman Ian Thompson. "We're working with the Ministry of Natural Resources because of the smoke and so on, but right now things are OK."

In the more northerly region of Sioux Lookout, fires have consumed more than 800 square-kilometres of land. Fire officials have started controlled burns at the back of one of the fires, in preparation for changing winds.

"When the wind changes and the fire starts to turn and blow the other way, it will run into a roadblock created by these fires," explained Deb MacLean, a spokeswoman for the Ministry of Natural Resources.

"The controlled fires will have burned out the land, leaving nowhere for this fire to go."

However, cautioned MacLean, changing winds also mean the smoke will start blowing right into the community of Sioux Lookout. While no evacuation has been ordered, MacLean said public health officials were aware of the situation.

"The uncontrolled portion of the fires still are posing threats," said MacLean. "Not only to tourism but also to the forestry industry because they have timber allocated for harvesting in the next five years."

The ministry says more than 700 Ontario fire rangers and 600 Ontario contract forest firefighters are involved in combating the fires, along with 276 firefighters from British Columbia, Alberta and the Northwest Territories.

All of the ministry's water bombers, supported by 13 water bombers from outside the province, are in operation, along with 92 helicopters.

"Our priority is to protect human life, property and forest values and we are allocating all available resources to battle these fires," Natural Resources Minister Jerry Ouellette said in a release.

In Manitoba, dry, hot weather has led to 600 fires so far this year. The northeast part of the province is the driest and where most of the fire activity is.

Heavy smoke resulted in the partial evacuation of two remote native communities.

More than 260 people with lung problems or in poor health have been taken from Red Sucker Lake and God's River over the past few days.

Large numbers of the evacuees were flown to The Pas.

Ontario fire managers continue to hope for rain.

"I got up this morning and my truck had a few rain drops on it," said LeClair. "And the robins were pretty excited, but we need a lot more than that."

Rain in northern Alberta has quashed forest fires there, allowing residents back into their homes.