KMART at Stockland Green Hills went into lockdown on Monday, with police officers called to the site.
The Newcastle Herald understands a threatening phone call was received at the store, which sparked the lockdown just before 1pm on Monday, June 17.
Kmart had reopened to the public later that afternoon.
The rest of Stockland Green Hills shopping centre remained open and was operating as normal during the incident.
Stockland Green Hills Centre management said earlier on Monday that they had not been told what was going on and were yet to release details on the incident.
Staff at nearby Harry Hartog book store confirmed the Kmart store had been closed for a period of time.
According to public accounts, Kmart workers acted swiftly to lock the front doors and take all staff and customers out the back of the building.
"About 12.50pm, officers from Port Stephens-Hunter Police District responded to reports of an incident at a business on Molly Morgan Drive, East Maitland," a NSW Police statement said.
"No persons were injured and an investigation into the matter has commenced."
It's understood police are investigating the threatening phone call and who might have been behind it.
