The national maritime safety regulator is investigating a luxury cruise line following allegations workers are being forced to live in overcrowded conditions below deck with no safe free drinking water, earning as little as $2.50 an hour.

The Maritime Union of Australia (MUA) said it received reports from a whistleblower working onboard the Carnival Encounter cruise ship currently docked in Darwin, prompting investigators from the Australian Maritime Safety Authority (AMSA) to board the ship on Monday morning.

In a statement, the AMSA confirmed it was looking into claims related to workers’ welfare onboard the ship.

The upper levels of a large cruise ship docked in a harbour.

The union says AMSA’s inquiry was sparked by reports from an anonymous crew member. (ABC News: Pete Garnish)

MUA Sydney branch organiser Shane Reside said over the past six months, the union had received hundreds of complaints about the international cruise line from workers, describing “horrifying” conditions, including galley stewards working in the kitchen being paid as little as $2.50 an hour. 

“They’re paid as little as $600 a month and sometimes required to work in excess of 10 hours a day for in excess of 30 consecutive days,” he said.

“I don’t think that any holiday is worth workers facing the kinds of exploitation that we’ve seen on these vessels.”

Mr Reside said he attempted to board the vessel in Sydney in December to investigate the allegations, but was refused access.

He said the whistleblower, who asked to remain anonymous as they feared losing their job, also reported workers were being made to live in very crowded living conditions, leading to the fast spread of skin diseases, and that crew members were being required to work while suffering from serious illnesses.

A large cruise ship docked in a harbour.

The Carnival Encounter is one of three Carnival Cruise Line ships in Australia. (ABC News: Pete Garnish)

The AMU has also received reports the only free water available to workers is potentially harmful, despite the Maritime Labour Convention requiring clean water onboard ships to be free of charge.

“The passengers and the officers on board get drinking water provided for free, but the crew are required to either drink the very poor quality drinking water in the tanks or they have to pay for their bottled water,” Mr Reside said.

“Seventy cents a bottle doesn’t sound like an enormous imposition by Australian standards, but if you’re only earning $2.50 an hour, then 70 cents for a bottle of water is actually a significant imposition.”

The Carnival Encounter is one of three Carnival Cruise Line vessels operating in Australia. The MUA claims the company uses loopholes to employ foreign crew members excluded from Australian employment laws.

The lack of a large cruise ship docked in a harbour.

Union representatives say they have received hundreds of complaints about the Carnival Cruise Line in recent months. (ABC New: Pete Garnish)

Mr Reside said based on the information that had been provided, the union believed such conditions were “endemic across the Carnival Cruise fleet”.

“It doesn’t seem like an aberration, it seems like a pattern,” he said.

MUA NT branch secretary Andy Burford said Carnival was bringing in workers from some of the world’s poorest economies while “generating billions of dollars in profit worldwide”.

“This is exactly what happens when you allow foreign-owned and controlled companies to sail the Australian coast, using Australian ports, carrying Australian passengers paying Australian fares, but who are completely immune from Australian law,” he said.

In a statement, an AMSA spokesperson said the agency investigated claims and complaints of seafarer health and safety issues in line with the Maritime Labour Convention, the Navigation Act 2012 and relevant Marine Orders, and would take action if breaches of the convention were found.

“The Australian Maritime Safety Authority takes the welfare of crew on board ships very seriously,” the spokesperson said.

The Carnival Cruise Line has been contacted for comment.