The carpark was sealed off and no-one was allowed into or out of the building.

The drama unfolded shortly after 10am when an employee discovered a questionable substance on a rug in the furniture department. Management alerted police at 10.30am and emergency procedures were activated.

Police officers, ambulance personnel and a fire brigade hazardous material team were on the scene within 10 minutes.

Contamination fears were heightened when a young female staff member walked out the front door carrying the crystals.

She was immediately isolated and positioned in a restricted area at the front of the store.

Clearly distressed, she was reassured by emergency workers but not allowed to leave.

Meanwhile shoppers and the rest of the staff were confined in the store. Hazard tape was positioned around the main entrance and emergency workers checked the building.

The white substance was sealed in a Hazmat container and taken away for testing. The all-clear was given at 11.10am and a stream of relieved people were escorted through the front door.

Some were upset about being detained but most understood the need to follow emergency procedures.

“It all seemed a bit over the top,’’ Ashley McGilchrist said.

“I went into Harvey Norman to do some shopping at about 10.45am. Ten minutes later the whole place was sealed off. We were told what was happening - some people kept shopping for a while but most watched the action from the front windows. A few people got stroppy when they weren’t allowed to leave.’’

Harvey Norman resumed trading after the emergency.