Police had also not ruled out that incident being connected to Friday's robberies, MacDade said.
On all three occasions, the assailant obscured his face and presented a pistol or claimed to be carrying a pistol.
''The first one [on Friday] involved the threat of a pistol but one was not seen,'' he said.
''The second robbery was armed.
''A witness in the second robbery chased the offender on Benhar St towards Scoular St and police would like to hear from anyone who may have witnessed this. The witness stopped chasing when the offender presented the pistol.''
Jewellery was stolen from the antique store, while cash and cigarettes were taken from the Elgin St dairy.
Police did not know if any vehicles were involved. None were seen leaving the scene.
The only description police could provide of the offenders involved in Friday's robberies was of a solidly-built male.
''They were disguised at the time,'' MacDade said.
''Police encourage anyone who has any information or who saw any suspicious activity in the areas on Friday to please contact Dunedin police.
''Alternatively, information which may assist our investigation can be provided anonymously to Crimestoppers.''
Late last month, police launched a campaign offering cash rewards for information which led to the prosecution of those selling black market tobacco in response to the rising tide of armed robberies of dairies.
Dunedin police (03) 471-4800, Crimestoppers 0800 555 111.
