Investigators have been told the trio broke into the store on McAdam Square in Croydon about 1.50am on Sunday.
The offenders disabled the security cameras inside the store before stealing $30,000 worth of jewellery.
The trio fled the scene shortly after, police said.
Investigators have released CCTV and images of three people who may be able to assist with the investigation along with images of some of the items stolen.
