Darwin lost its chance of hosting a $5 billion gas plant and expanding its Sunrise fields, following announcement by Woodside Petroleum Ltd that its joint venture partnership with ConocoPhillips, Shell and Osaka Gas, have opted to build instead a floating platform in the Timor Sea.

According to AAP, the Greater Sunrise LNG fields, situated 450 kilometres north of Darwin, contain dry gas reserves of 5.13 trillion cubic feet and 225.9 million barrels of condensate, as Australia competed with East Timor to secure the billion dollar project that could have further enlarged the fields.

The country maintains an agreement with East Timor, signed in 2007, to administer the Joint Petroleum Development Area and develop the Sunrise fields in pursuit of the best commercial advantage available.

Woodside chief Don Voelte told AAP that the company's partners opted for the floating LNG processing to take advantage of a wider range of social investment, employment and training opportunities with East Timor.

He added that maintaining a floating platform offers much significant petroleum revenue projections following the joint ventures' careful evaluation of technical and commercial findings, as he stressed that they even considered building an onshore facility at either Darwin or East Timor yet in the end a floating platform emerged as the best option.

Woodside has earlier announced its intentions to put up a floating processing facility for the Sunrise gas instead of maintaining a base in Darwin, in an apparent attempt to circumvent the implementation of the national government's controversial carbon emission trading scheme (ETS).

AAP has reported that Mr Voelte informed the company's investors in 2008 that Australia was in danger of losing Sunrise as the first casualty in enforcing ETS, which federal authorities, in a recent pronouncement, intend to shelve at least until 2013.