Police have identified the ‘suspicious' white powder which caused an area around the Greerton Post Office to be closed last week.

The substance is believed to have been rice starch mailed from India.

Emergency services dealt with a suspicious package at the Post Office in Greerton on Tuesday, August 25. Photos: Andrew Campbell.

A hazardous material response was launched when a white substance was seen leaking from an envelope at the post office on Chadwick Road just after 8am on Tuesday, August 25.

At the time of the incident, scene commander Aaron Waterreus told SunLive the Post Office was closed to the general public for safety precautions.

Four people, including two firefighters and two workers, were decontaminated and the scene was eventually cleared just before 12pm.

Police are investigating the matter further.