Ammonia leak near Perth Airport

Firefighters are tackling an ammonia leak at a Coles distribution centre near Perth Airport.

The supermarket chain said the gas leaked in the building's cooling system on Dunreath Drive on Monday afternoon and staff were evacuated about 1.45pm.

"All team members were evacuated safely and we are working with emergency services to find and fix the source of the gas," a spokesman for Coles said.

"Emergency services have allowed our team to re-enter the unchilled section of the distribution centre, however the chilled section remains closed.

"We are working to minimise the impact on store deliveries."

Five fire crews and a specialist risk officer are dealing with the incident, the Department of Fire and Emergency Services said.