Anyone with information is asked to contact Police on 105, quoting file number 210415/6346.
Crimestoppers can be called on 0800 555 111, as an anonymous service.
Police have made a string of arrests in relation to the incident on April 15, in which a gun was fired soon after 9am at the hotel in Auckland's Viaduct. Police blame the Head Hunters and Mongols gangs.
Earlier this month police asked the public to help find another Head Hunters gang member, Fred Tanuvasa.
Meanwhile, a 22-year-old Head Hunter gang member was arrested last month. He is also facing a number of other charges relating to unlawfully possessing firearms and ammunition, drug dealing and participating in an organised criminal group.
"A large amount of cannabis and cash amounting to tens of thousands of dollars were also seized," Detective Inspector John Sutton said.