Shops at Westfield Warrawong were evacuated this afternoon after police were called to investigate a suspicious package at Australia Post.
A police media spokeswoman said police had responded to a call around 2pm.
Police cordoned off and evacuated a section of the shopping centre containing the post office.
A fire brigade hazardous materials team was also at the scene.
Lake Illawarra police and specialist officers attended the scene about 2.30pm and examined the item before declaring it safe about an hour later.
Employees were then permitted to return to work.
Police believe they may know who was responsible for the package, but treated the threat seriously as a precaution.