Harbour hosts world's biggest ocean liner

As captain of the largest ocean liner ever built, Kevin Oprey has met famous stage writers, Formula One drivers and US presidents.

But he still finds Sydney harbour particularly captivating.

"You can't think of a better harbour to come into," he said on the ship's bow.

"It's so beautiful to look at with the Sydney Harbour Bridge and the Sydney Opera House.

"It's just a wonderful experience."

His ship, the Queen Mary 2, has docked in the harbour city as part of its 10th-birthday world voyage, which includes a circumnavigation of Australia.

When the 345-metre ship first visited Sydney in 2007, it caused traffic havoc as thousands flocked to admire the sight at peak hour.

Capt Oprey says it's a huge responsibility heading a ship with 2500 guests and 1200 crew.

On Wednesday morning, 122 uniformed staff posed for a celebratory portrait on the ship's bow with the Harbour Bridge in the background.

The 151,400-tonne ship cost $800 million to build and is the only ocean liner still in service.

It's home to the largest ballroom and library at sea, and has a planetarium, 3D cinema, kennel for transatlantic voyages, 14 bars and clubs, and more than 10 restaurants and cafes.

More than 160 chefs are in charge of cooking 15,000 meals a day.

Executive chef Nicholas Oldroyd says he's taking advantage of Sydney's seafood.

"I've got so much fish coming on board," he said.

"For the barramundi, we've got almost 500 kilograms of fish coming in."

The Queen Mary 2 will leave the harbour at 9pm (AEDT) on Wednesday and return to Sydney on March 14 before finishing its Australian leg in Cairns five days later.