Port Moresby, PNG: ExxonMobil is on the verge of announcing financial closure on its $US15 billion ($A16.7 billion) Papua New Guinea liquefied natural gas project now that it has signed the final off-take agreement needed for it to proceed.

Taiwan's largest energy importer, CPC, has finalised the terms of a contract under which it will take 1.2 million tonnes a year of LNG for 20 years from the PNG project, a joint venture between ExxonMobil, Oil Search, Santos and others.

At the release of Oil Search's annual results last week, its managing director, Peter Botten, said financial closure on the LNG project would be achieved within a month. The CPC deal would occur during that time, he said.

ExxonMobil's vice-president of LNG, Ron Billings, said the sale and purchase agreement with CPC would help deliver cleaner fuel to meet Taiwan's growing energy demand.

“'It also marks a significant step forward for the PNG LNG project,”' Mr Billings said. “With this sale and purchase agreement, all of the project's production capacity has been committed on a long-term basis”

The PNG gas project is expected to start exporting 6.6 million tonnes of gas a year from 2014.