The men threatened the shop assistant, took cash from the till and alcohol before running into Rossister Place where police believe a vehicle was waiting.
Police said the men turned up at the Tuhikaramea Superette the next evening and threatened Khattar.
Acting Detective Sergeant Andrew Mortimore said: "They threatened the two shopkeepers, demanding cash and cigarettes before leaving with both."
Shop assistant Vijay Kumar chased them and got a registration number. Two hours later the men smashed a window at the TAB on King St and threatened the staff member with a pistol, demanding access to the safe. They left the scene with cash and other items.
Police said in all three incidents, the offenders were wearing similar clothing and made little or no attempt to disguise their identities.
They are warning the men should not be approached and that they are concerned with the escalation in their activity.
Anyone with information should call Acting Detective Sergeant Andrew Mortimore at the Hamilton Police on (07) 858 6200 or Crime Stoppers on 0800 555 111.