A cruise in Australia descended into a “bloodbath” Friday when a wild brawl erupted after someone stepped on another passenger’s flip-flop.

Dramatic video obtained by Australian radio station 3AW shows a group throwing punches, kicking and grappling on the floor of the Carnival Legend cruise ship — while others scream wildly and attempt to hold back the aggressors. Eventually, security guards stepped in — even kicking at two combatants in an attempt to separate them. One security guard is shown trying to hit the cellphone of the passenger who was filming.

The fight broke out shortly after a 12:45 a.m. argument aboard the ship, while it was passing through New South Wales, about 137 miles off Jervis Bay, police told Nine News Australia.

Cops kicked six men and three teenage boys off the ship for taking part in the fight — and 14 other passengers, including women and children, also left, according to the report. The 23 brawlers — all members of the same extended family — were removed after the ship docked in Eden, north of the New South Wales-Victoria border, the outlet reported.

One passenger, identified only as Zac, told 3AW on Friday morning that security had locked him in his room overnight and he was going to be removed from the ship.

Zac claimed the drama between his family and another party began when someone had stepped on a “thong” — the Aussie word for a flip-flop shoe.

“This is all over a thong — not a foot — a thong being stepped on and being instantly apologized for,” Zac told the outlet. “What happened there and then was apologized for.”

The man claimed that security guards followed his family “at every possible moment” and caused a lot of the trouble.

“The first hit was thrown by security towards, not just my daughter and my sister-in-law, but my wife as well,” he told the station — adding that the guards also targeted him and his son, “taking turns pounding us in the face with knuckle dusters and steel-cap boots.”

But passengers told the outlet that the family had been causing problems for days — describing the whole ordeal as a “cruise from hell.”

“They were looking for trouble from the minute they got on the ship,” one woman said.

David Barkho told the station that his son was on the ship and desperately called him at 1 a.m. asking for help.

“He said, ‘Please Dad, please, call the federal police,’” he said. “I could hear a lot of screaming, crying in the background.”

Another passenger told Nine News that the troublemakers had previously threatened to stab and throw people overboard.

“We are so scared after witnessing a traumatic experience with yet again the same offenders,” the passenger said. “It was a bloodbath.”

Carnival told the station that it takes “a zero tolerance approach to excessive behavior that affects other guests.”

“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 statement continued. “The ship’s security team is applying our zero tolerance policy in the interests of the safety and comfort of other guests.”

The 10-day South Pacific cruise is scheduled to come to a close in Melbourne on Saturday.