Police have released CCTV images from a Sydney bank robbery nearly 30 years ago.

On the afternoon of December 21, 1990, a man allegedly armed with a small handgun entered a bank on the Princes Highway at Rockdale.

He threatened several employees and got away with $52,000.

Police are asking for anyone who can identify the man depicted in the CCTV to come forward, with fears he was involved in a second robbery in the area immediately after.