About a fifth of homes have been destroyed in Fort McMurray, a Canadian city ravaged by a huge wildfire, the local MP has told the BBC.

After touring the damage David Yurdiga said it might be years before the city was running normally again.

More than 100,000 residents of the city and surrounding area fled after an evacuation order was issued.

Officials say the fire, now burning for a week, grew more slowly at the weekend than first feared.

Firefighters held key areas and the blaze now covers about 1,610 sq km (620 sq miles) - less than the 1,800 sq km (700 sq miles) estimated on Saturday.

Yurdiga said while most of the city was intact the area was still too dangerous for residents to return home.

"An estimate: 20% of the homes have been burnt, but the majority of homes are standing, no damage at all," Yurdiga said.

"So you know what? It's a lot better than I thought it was."

On Sunday, fire chiefs spoke of getting a "death grip" on the fire, which has been fed by hot weather and tinder dry terrain.

"With a little help from mother nature and a bit of a break in the weather, and all the hard work of all the firefighters we were able to hold most of the line in Fort McMurray," said Chad Morrison from Alberta wildfire.

But it could be months before the fire is fully brought under control. Officials warned only significant rainfall could fully halt its spread.

The fire is being blown east away from communities, but still threatens to cross from Alberta province into neighbouring Saskatchewan.

Air quality warnings have been issued for Saskatchewan and Northwest Territories, with locals advised to close windows and doors due to smoke.

The final evacuations of 25,000 people who headed north from Fort McMurray after the blaze began was completed on Sunday.

The blaze destroyed whole neighbourhoods in Fort McMurray. Photo: Reuters/BBC.

Schools in the provincial capital Edmonton are arranging for displaced families to send their children to local schools from Monday.

No deaths or injuries have been reported from the fire, but two people died in traffic accidents during the mass evacuation.

The fire is expected to be the most expensive natural disaster in Canadian history, with insurance costs alone already running into billions of dollars.

Fort McMurray is in the heart of Canada's oil sands country, and the region has the world's third-largest reserves of oil. Workers at major oil companies have also been evacuated.

As much as a quarter of the country's oil production has been halted by the fire, raising concerns about the effect on the Canadian economy.