The Outer Harbor project, to be built in Port Adelaide, will produce 110 petajoules per annum of LNG to pass through the terminal and into local and interstate gas networks.
The project's approval should reduce gas shortages in the southeast of Australia from mid-2026 and beyond, Venice Energy said.
Origin, which is the subject of a Brookfield-led consortium's $9.67 billion takeover, did not immediately respond to Reuters' request for comment.
"The reason we have not entered an agreement to date is because there are cheaper sources of domestic gas supply available and these provide the best chance of keeping gas prices lower for our customers," an Origin spokesperson had said in August last year.
Venice Energy Chair Kym Winter-Dewhirst said that Origin and Venice Energy’s subsidiary Venice Regas will enter into an exclusivity arrangement, allowing for the completion of a fully-formed terminal use agreement over the coming weeks.
Last year, Australia's parliament passed legislation setting a price cap on natural gas for one year, deterring development of new supply.
The potential deal would be a big boost for Venice Energy's project in Port Adelaide.
The deal could come as a blow to iron ore baron Andrew Forrest-owned Squadron Energy's Port Kembla facility in New South Wales, which was expected to take its first gas shipment by end of 2023.