The deal was signed with Norway's Hoegh LNG and DSME E7R, a subsidiary of Daewoo Shipbuilding and Marine Engineering.
In a joint statement, the companies said they had agreed to work together to assess future options.
"We have commenced an economic and technical feasibility study in order to provide a competitive option to any gas owners in the Gulf of Papua," they said.
If the project goes ahead it could be operational by the end of 2014 and produce up to 3 million tonnes of LNG per year, processed at an onshore plant in the Gulf province.
The vessel will be built at the DSME shipyard in South Korea, and infrastructure construction in PNG is expected to create 300 jobs.
Papua New Guineans will be trained to operate the systems and processes of both the ship and the processing facilities, which will be jointly operated by the three parties.
Plans by Flex LNG for a similar FLNG project in PNG faltered after joint venture partner Rift Oil was taken over by Canada's Talisman Energy last year.
As reported by PNN in October last year, Talisman believed FLNG to be "losing flavour" as it built up its asset base in PNG.