China's Sinopec <600028.SS> has agreed to increase its stake in the Australia Pacific LNG joint venture to 25 percent and buy more supply from the project, partner Origin Energy said on Monday.

China Petroleum Corporation (Sinopec) will buy an additional 10 percent stake in the project and 3.3 million tonnes a year of LNG through 2035.

As a result, Origin Energy and ConocoPhillips' stakes will reduce to 37.5 percent each.

The deal would finalise the marketing of the second train of the project, Origin said.

(Reporting by Sonali Paul)