Royal Dutch Shell will construct the biggest floating man-made object ever, a natural gas processing plant longer than four football fields and more massive than any aircraft carrier.

The "Prelude FLNG" facility, to be anchored off the Australian coast, will be made of 260,000 tons of steel — five times more than Sydney's famed Harbour Bridge, Shell said Friday.

It is designed to take in the equivalent of 110,000 barrels per day in gas from undersea fields 200 kilometers off Australia's Northwest coast and cool it into liquefied natural gas, known as LNG.

Australia is awash in natural gas, and is eager to sell it to the booming economies of Asia.

In order for natural gas to be shipped overseas, it must be cooled to -260 degrees Fahrenheit. At that temperature the gas becomes a liquid that takes up just 0.2 per cent of the volume of the gas, allowing more gas to be packed onto a ship.

The Australian oil and gas company Woodside is set to begin production at a giant onshore liquid natural gas facility in Western Australia this year and is considering doubling its size.

Shell claimed the plant will be able to withstand Category Five cyclones, the worst type of storms, and is planned to remain moored above the Prelude gas field for 25 years after completion.

Cost not disclosed

Shell said the plant will be built in a South Korean shipyard but did not say how much it would cost.

A company spokeswoman declined to set a date for the plant's completion date, but noted the Prelude gas field is scheduled to start production around 2017.

"We don't give specific guidance on project level spend, but we are making a substantial investment in Australia LNG," said spokeswoman Kirsten Smart in an email.

Shell plans $30 billion in various investments in Australia over the coming five years, the company has said.

"This project is certainly competitive with more traditional Australian LNG developments on a cost and economics basis," Smart wrote.

Financial newswire Dow Jones cited Australia's Resources Minister Martin Ferguson as saying the project will benefit the country's economy by creating around 1,000 jobs and contributing $12.8 billion US in tax revenues over 25 years.