Passengers have said they were "scared for their safety" after violence erupted on board their 10-day cruise in the South Pacific.
The Carnival Legend was forced to dock in Eden, NSW, on Friday morning following disturbing reports of violent clashes between two groups of passengers on board.
About 30 people were reportedly involved in the brawls.
The ship, which was due to return to Melbourne on Saturday morning, is now docked in the coastal town of Eden, close to the Victoria border.
Six Australian Federal Police officers have boarded the vessel.
The Herald Sun has been told members of a family had been put under "house arrest" on the ship by security guards.
"There are about 20 of the family, older people, teenagers and young kids with them," a passenger, Naomi, said.
"They were loud, alcohol affected and things like that."
Naomi said there had been a number of fights on board, including in a nightclub and in an elevator the next day.
"And a big fight on the lido deck, which went on for about 45 minutes," she said.
"Lots of yelling people being threatened. Being called dogs in the smoking area. A pool was full of children, people were pulling their children out of the pool because they were crying and scared.
"Last night they attacked one of the security guards."
Passengers described how they locked themselves in their cabins as violence between two large groups broke out on several occasions.
They said threats had been made to stab and throw people overboard during what was described as a "cruise from hell".
"We are so scared after witnessing a traumatic experience with yet again the same offenders. It was a bloodbath," the passenger told Nine News.
"We will not be leaving our cabins and are truly scared for our safety and what could happen in the next 24 hours."
Passenger Kellie Petersen, who was on the cruise with her husband and their three children, aged 11, 9 and 6, said trouble on board had been "brewing for days".
"They were looking for trouble from the minute they got on the ship," she told Melbourne's 3AW.
"My husband said to take it away, because there's kids here, and five of them surrounded my husband. They told us to watch our backs."
David Barkho told 3AW he got a 1am call from his son George, 20, who was a passenger on board, saying he had been injured and needed help.
"He said, 'Please Dad, please, call the Federal Police'," Mr Barkho said.
"I could hear a lot of screaming, crying in the background."
Barkho said George had seen "a lot of people bleeding, a lot of people down on the ground".
A photo supplied to the radio station shows George being treated for an apparent cut on his head.
Barkho also claimed security staff deleted images of the violence from George's phone.
In a statement to news.com.au, the ship's operator Carnival Cruise Line said staff had taken action against a small number of "disruptive guests".
"Safety is the number one priority for Carnival Cruise Line, we take a zero tolerance approach to excessive behaviour that affects other guests and we have acted accordingly on Carnival Legend," a spokesman said.
"The ship's highly trained security staff have taken strong action in relation to a small group of disruptive guests who have been involved in altercations on board.
"The ship's security team is applying our zero tolerance policy in the interests of the safety and comfort of other guests.
"Carnival Legend is currently on a 10-day South Pacific cruise scheduled to be completed in Melbourne tomorrow where the ship is currently homeported."
The incident on the Carnival Legend comes days after a group of Australian men were kicked off a P & O cruise ship, which was forced to return to Sydney after an out-of-control bucks party on board.
Police met the Pacific Explorer vessel at Bradleys Head on the north shore of Sydney Harbour on Sunday and removed six men and a Russian woman after a fight took place on the ship that morning.
Speaking to Nine News, one of the men involved in the brawl said it was "one hell of a bucks party, that's it".