SYDNEY Woodside Energy said on Wednesday "positive progress" was being made on wage disputes at Australia's largest liquefied natural gas (LNG) facility even as a union alliance said key differences remained.

Woodside's North West Shelf, along with Chevron's Australian LNG operations of Gorgon and Wheatstone, supply about 10% of the global LNG market.

About 99% of workers at offshore platforms that supply gas to the Woodside facility have voted for industrial action, with any strike potentially disrupting shipments and sending prices for the super-chilled fuel higher.

After the vote, the union can decide whether to go ahead with any action, which must take place within 30 days.

"Positive progress is being made and the parties have reached an in-principle agreement on a number of issues that are key to the workforce," a Woodside spokesperson said in an emailed statement.

"We continue to engage actively and constructively in the bargaining process."

China and Japan are the top two buyers of Australian LNG, followed by South Korea and Taiwan.

The Offshore Alliance, which combines the Maritime Union of Australia and Australian Workers' Union, however, said differences on key issues remained.

"Woodside are well off the pace on key bargaining issues including job security and remuneration," the union said in a message posted on Facebook on Wednesday.

Last week, Australia's labour regulator cleared the way for strike action for Chevron workers if they vote in favour of it.

Chevron workers will begin voting "over the next week", the union said.

(Reporting by Renju Jose and Lewis Jackson in Sydney, and Florence Tan in Singapore; Editing by Jacqueline Wong and Miral Fahmy)