Fire crews and police have been called to a scrub fire off Cathedral Avenue, near the John Willcock Link flyover.
Police have diversions in place for south-bound traffic along Cathedral Avenue, as fire crews tackle the fire.
The blaze was suspected to have been deliberately lit, police said.
Drivers should be wary of limited visibility in the area caused by heavy smoke.
The area of scrub affected by fire is bordered by Durlacher St.