One man was wearing a grey hooded top and dark trousers, while the other a dark-coloured top with a hood and dark trousers. The top had a logo on the back.
Police are also appealing for any sightings of a red 2004 SS Commodore that was in the area at the time of the robbery.
Last month there were unconfirmed social media reports circulating of cash being scooped off the street by a passing motorist after the robbery. Police would not comment.
Moments after the robbery former policeman Gavin Benney, now a Whangarei District Council councillor, spotted the two masked robbers. He stopped the pair but one pointed a gun at him before getting into a red Holden Commodore in Second Ave.
Benney was walking from Forum North to the central library when the masked men ran past him. One was carrying a bag and the other was empty-handed.
Anyone with information should contact Whangarei police on 09 430 4500 or Crimestoppers anonymously on 0800 555 111.