Luxury cruise lines are finding a booming market in residential suites.

Crystal Cruises President and CEO Edie Rodriguez revealed at the Australian Cruise Association’s Sydney conference this week that 250 past guests had put their names on the waiting list for 144 apartments aboard the line’s newest ships.

Some suites offer 4,000 square feet of living space, and owners can take advantage of the Nobu restaurant and either mingle with 1,000 paying guests or simply lock themselves away in luxury.

They will also be able to play with toys like a submarine and helicopter.

The apartments are on the upper floors of the new ships with private elevators and butlers.

The residencies, the prices of which are yet to be revealed, are all part of a major plan to create Crystal Cruises into a lifestyle brand with private jets, five luxurious ocean liners, an expedition yacht and a fleet or river ships.

Crystal Cruises is the second cruise ship company to offer guests the chance to make a liner their home. But more are on the way.

The World has 165 private residences. It is believed Jamie Packer’s mother Ross has two apartments aboard the vessel, which literally sails around the world.

At 644ft, the studio flats sell for more than USD$1million and the top suites cost up to $13million .

The Utopia, a 200-unit condo cruise ship that will be almost twice the size of The World, has been planned for some time, with a $US1.1 billion price tag and apartments between $3 million and $22 million.

A river ship, The Marquette, is also being planned in the US which will have 185 residences navigating the 5,500 miles of rivers and 1,100 miles of Intracoastal Waterways in the US year-round.

The Marquette is currently 42% presold and expects to launch in 18 months. Its apartments range in cost from $248,000 to $900,000.