Jasper National Park says wildfires in the area have grown by thousands of hectares and are set to expand further on Friday.

The park says the wildfire remains out of control and has grown by about 7,500 hectares, bringing it to about 39,000 hectares.

It says the new growth was expected and primarily on the south end of the fire.

The park is anticipating more growth Friday because of expected hot and dry weather.