The 16.3 million tonne per year capacity plant expects to sell the supply in two tranches with final bids for the cargoes due by Jan. 26, the source said.
The unexpected tender signals a delay of around three months to reforms of how NWS will market supply, which will see the plant's six stakeholders be allowed to market their equity share of spot cargoes directly.
NWS puts the spot supply up for grabs in an open tendering process, in which stakeholders compete with other companies to purchase supply.
The six stakeholders are BHP Billiton, BP, Chevron, Japan Australia LNG, Shell and Woodside, which operates the plant.
The facility launched a separate tender to sell three cargoes on Jan. 5, bids for which closed to today. A winner is set to be announced on Friday.