He took the cruise, which left Sydney on August 3rd,  with his wife, and their 18-month-old child and were among a large extended family group.

While still onboard, some passengers are saying there was a brawl. Sometime after that brawl, the man was found by another passenger in the early morning hours dead on the floor in a public restroom.

The cruise line denies this account, saying a brawl never took place, but confirming that the man was found dead in a public area of the ship. They say the man "passed away".

Another passenger onboard has said the captain made a general announcement that the (31-year old) man had died as a result of a heart attack. Another case of "heart attack" that was incorrect is here

The Department of Foreign Affairs and Trade (DFAT) says it is giving consular assistance to the man's family.  DFAT says it understands a "crime scene" has been established on the ship.

A NSW Police Force spokeswoman said police in Noumea in New Caledonia were investigating the matter.
Cruise Ship Passenger Dies Onboard
Family Man Dies In Public Area Of Cruise Ship
P & O Pacific Sun - August 7, 2007
The ship left port at the Isle of Pines for Ouvea on Monday night and iis due back in Sydney this Saturday.

It will be interesting to see if there was a murder onboard, if the tiny republic will hold an inquest and ultimately have charges filed, inspite of the bad publicity that would give to the "hand that feeds" them, the cruise industry.

UPATED: AUGUST 11, 2007
Passengers onboard the ship say the man was definately involved in a brawl, and had asked security onboard the ship for help. They say. Two women ran into the ship's Legends Bar about 1.30am screaming for help. Several passengers say the man took a "king-pin" hit during the brawl. Later, he was found was dead in a public restroom onboard.

One passenger said that about a dozen men had been doing shots of liquior and tension had been building before the brawl broke out. He claims that the men should have been cut off alcohol long before the brawl began.
Another passenger, who witnessed the entire incident says police never interviewed him. The Dianne Brimble "dancing" detective was on the scene.
Cruise Line: P & O Cruises
Ship: Pacific Sun
Built: 1986 (Jubilee)
Refurbished: 2004
Registry: Bahamas
Size: 47,262 Gross Tons
Length: 732 feet
Passengers: 1,896
Crew: 670

Bow Webcam: > Here

Event Date: August 7, 2007
Cruise Bruise:  Death Onboard
Bruise Location:  New Caledonia
Age:  31
Home Town: Sydney, Australia
Cruise Line: P & O Cruise Lines
Ship: Pacific Sun
Details:

The man has not been named at this point. Reports say the man, a father age 31, had won the eight-night South Pacific cruise in a Sydney radio station 2GB contest.
The Pacific Sun had been scheduled to dock at Oueva in the Loyalty Islands, north of New Caledonia. The ship altered course to Noumea, New Caledonia, after the man's death.
The Noumea Accord (1998) and consequent Organic Law (May 1999) provided the constitutional framework under which New Caledonia is governed today and defined its institutions.  They also defined New Caledonia's relations with metropolitan France for the following 15-20 years and set out a timetable for New Caledonia to assume responsibility for most areas of government.
Quick Primer On New Caledonia

New Caledonia is the third largest island in the Pacific Region after Papua New Guinea and New Zealand. It is located in southern Melanesia, at a latitude of 19° - 23° south and at a longitude of 158° - 172° east.

New Caledonia is located almost directly between Australia and Fiji, New Caledonia is billed as "France's Best Kept Secret".
The French high commission in New Caledonia says crime in 2004 increased by almost 18 percent over 2003. It says a total of more than 13,000 crimes were reported, with increases in the capital, Noumea, of more than 25 percent.
Looking at the breath-taking photograph above, it is hard to imagine any crime at all.

The high commission says though,  just under half of the police cases were solved in 2004. This is a similar percentage to murder only crimes solved in many U.S. cities.

The population of New Caledonia is 221,943. The population of Noumea is 65,100. The population is primarily indigenous Melanesian Kanaks who account for 43% of the population while 34% are of European descent, mostly French. The national language is French.

Other P & O Cruise Line cases:
Pacific Sky Dianne Brimble Death Onboard
Pacific Sky Kasmira Sewpershad Drink Spiking
Pacific Sky Andrew Gready Overboard Death
Pacific Star Voyage Leaves Port In Unsafe Seas
Pacific Star Expels Film Crew
Pacific Star Dumps Oil On Tiny Island
Pacific Sun Evicts Schoolies
Noumea
New Caledonia