The launch took place on Saturday with the 365m-long hull floating out a dock and anchored for more construction work.

The Malaysian oil company said this milestone was reached in less than 10 months since the first steel was cut in mid-2013, while the hull was equivalent to three NFL football fields in length.

"It is an impressive achievement that we launch the hull within a short time frame following the keel laying process that began on 6 January 2014," Petronas vice president Abdullah Karim said.

"In addition, the project has also achieved more than 5.5 million total safe man-hours since the project commenced in March 2012 with no occurrence of loss time incidents at the project site."

Petronas' first FLNG plant will be moored at the nearby Kanowit field and is targeting 1.2 million tonnes per annum with first production by late 2015.

It said the vessel will be the world's first FLNG in operation - with first gas from Shell's long-heralded Prelude FLNG project expected in 2016 although its 488m-long hull was completed in December.

Petronas' second FLNG vessel is under construction and targeting 1.5Mtpa from a mooring at the Rotan gas field off the Malaysian coast of Sabah with first production expected by early 2018.