Ichthys managing director Louis Bon was there for the traditional coin ceremony event, placing a newly minted Australian gold coin under the keel block for good luck.

"In a year that will see many major milestones for the Ichthys LNG project, this is a very big moment," he said.

"The FPSO is the facility that will be used for condensate dewatering, stabilisation, storage and export - so its importance cannot be overstated.

"With only a few years until first production, all of our major offshore facilities are taking shape."

Project operator Inpex said most pieces of the FPSO had already been incorporated into blocks ahead of the keel laying.

"These blocks will be combined to create mega blocks, which are then lifted, skidded and welded at the Daewoo dock to form parts of the FPSO and are outfitted and erected separately," it said of the modular construction work ahead.

Once complete the 336m by 59m FPSO will be towed 5600km to the Browse field in northern offshore Western Australia.

Inpex said the vessel was designed to hold more than 1 million barrels of condensate to offload into crude tankers for export shipments.

The project's LNG plant is under construction near Darwin.

The project is targeting 8.4 million tonnes per annum of LNG capacity and first exports in 2016.