West Auckland's alcohol licensing trusts have been found guilty of misleading the public in claiming that 47 percent of profits were given back to the community.
The Advertising Standards Authority said the two trusts - Waitakere Licensing Trust, and the Portage Licensing Trust - had not provided enough evidence to support that claim.
Both trusts hold a monopoly for alcohol licensing in the area.
Watchdog West Auckland Licensing Trusts Action Group filed a complaint against advertising by the trusts to the authority.
Its spokesperson Nick Smale said their research had found that over the past six years the amount of profit returned to the community had only been between 4 and 23 percent.
"It's vindication that what we've been saying is right, that the information they were putting out in the lead up to the election was not able to be substantiated. Basically they were misleading the public about how much money they were giving back," he said.
Mr Smale said he was disappointed by the actions of the two trusts.
"The decision, whilst it's great ... it's too late for us to have the right information out there in front of people when they were casting their votes [for the election of the trusts] a month or so ago," he said.
Mr Smale said the West Auckland Licensing Trusts Action Group managed to win a seat on each of the trust boards, but the two trusts had tried to delay the decision of the authority being released until after the elections.
"You can look at their submissions to the Advertising Standards Authority, they threw everything at this and lawyered up," he said.
"This one really went into procedural issues and technicalities and everything just to slow things down - it's very frustrating."
Waitakere Licensing Trust has been contacted for comment. Portage Licensing Trust declined to speak about the decision.