The Auckland Regional Council has warned ferry operator Fullers it could face harsh penalties if there is a repeat of an incident where one of its ferries abandoned 120 people on a Waiheke Island wharf on Saturday night.
Fullers Group claimed the vessel did not take the passengers because it was full and the master deemed it unsafe to take any more on board.
The stranded passengers - including a pregnant woman - were left to spend the night in the open.
They waited almost eight hours until the next ferry.
ARC chairman Mike Lee dismissed the company's explanation for what happened as "nonsense" and said he was appalled at the passengers' treatment.
"We believe this is the second time Fullers have left people stranded on Waiheke, with an incident over New Year. Two stranding incidents are a matter of real concern.
"We have been discussing the situation with the Auckland Regional Transport Authority and we will be writing to Fullers and asking for procedures to be put in place to prevent this happening again.
"The ARC has a relationship with the company worth millions of dollars in bus and ferry contracts and we feel we have the power to make them listen."
The ARC, which subsidises some public transport services, would investigate the ferry operator's actions.
"The feeling is with ferries that you take people to an island, you should be able to bring them back," said Mr Lee, a Waiheke resident.
"In the past the company has always done those sort of things."
Mr Lee said recurrences could damage the island's tourism industry and upset relations between the ferry company and residents.
Maritime Union national vice-president Garry Parsloe blamed the incident on a shortage of trained staff and said it was not an isolated case.
He cited an incident in December when passengers in Devonport were apparently sent to Auckland in taxis because overworked staff could not make the return trip.
Danny Marshall, who was stranded on the island with his 11- and 13-year-old children after a family function, hit out at Fullers Group's virtual monopoly on the run.
"If you miss the last bus, you can catch a cab, but we had no option, we had nothing."
Fullers Group chief executive Douglas Hudson said the company regretted the incident but was not solely to blame.
He said it assigned a larger than usual ferry because it expected a large crowd from a dance party at Stonyridge Vineyard.
The company was not carrying a large number of vacancies but it did not have staff on call to put on another boat in the early hours of Sunday.
Fullers would meet police and dance party organisers.
Meanwhile, two men who allegedly broke into the ferry terminal when they were stranded were arrested on charges of burglary and unlawfully being on property.
Some of the waiting passengers reportedly broke into the ferry terminal seeking shelter from the cold.