A supermarket on Queensland's Gold Coast has reopened its doors following a violent armed robbery that left a staff member with serious injuries.

The IGA store at Ormeau on the Gold Coast hinterland was targeted in two separate armed robberies early yesterday morning.

A brick was hurled at a window around 1:00am (AEST) and a group of thieves tried to break into a locked office.

A few hours later, another group of thieves forced open the roller door, assaulted the store manager and forced him to open a safe containing a small amount of cash.

Two cleaners were beaten with a crowbar before all three employees were tied up.

One cleaner was later taken to hospital in a serious condition.

The store reopened yesterday afternoon after forensic officers examined the scene.

Counselling is being offered to the employees left shaken by the violent hold-up.