Evacuees returning to Fort McMurray in Canada, which has been ravaged by a huge wildfire, may be greeted by scavenging black bears.

More than 2,400 homes and buildings were destroyed by the blaze and the entire town had to be evacuated which broke out at the beginning of this month.

Some 90,000 residents are hoping to return to Fort McMurray next month, with some fire officials confident that 90% of the city remains intact.

But authorities warn that returning residents may have to contend with black bears who have been prowling the streets in search of food.

The bears have wandered into the town in greater numbers since the wildfire's outbreak and the local populace being displaced.

"They are smart and adaptive. They can smell food from miles away," said Brendan Cox, a fish and wildlife enforcement spokesman.

"Just as you and I go to the nearby grocery store, or our favorite restaurant, the bears continue to return to a particular food source".

Some residents are due to return to Fort McMurray on June 1.

The city is nestled among prime bear habitat in northern Alberta's lush boreal forests.

It is estimated that there are 40,000 bears in the province, many of which will be searching for food after a nearly six-month winter hibernation at just the time residents are returning home.

The bears can weigh up to 150 kg.