A bushfire near one of the largest coal-fired power stations in Australia has been brought under control.

The fire was spotted some time after midday (AEDT), about one to two kilometres from the Bayswater power station near Muswellbrook, in the Hunter Valley region of NSW.

The blaze spread over five hectares and forced the closure of the New England Highway in the north-bound direction.

Crews brought the fire under control within a couple of hours and the highway has since been reopened.