A hearse delivered his coffin to the business on Bank St and was taken inside about 11am. About 150 people gathered to pay their respects and included family, friends and neighbours from Raumanga.
A relative said Hart had been tattooing for about 30 years and was a gifted artist who had touched many people with his work.
As the coffin was loaded back into the hearse onlookers performed a haka.
Hart was a member of the Highway 61 gang and there was a large contingent of gang members on motorbikes that lead the hearse away up Bank St to Pipiwai, about 11.55am.
Police said the death had been referred to the Coroner.