MELBOURNE, Aug 18 (Reuters) - Origin Energy's CEO said there is unlikely to be a gas supply shortage in eastern Australia in 2023 as liquefied natural gas (LNG) exporters have enough uncontracted volumes to avert a shortfall forecast by the competition watchdog.

"I'd be confident that there would not be shortfall based on the gas that's available in the market and the response by the (LNG) projects," Origin Chief Executive Officer Frank Calabria told analysts on an earnings call on Thursday.

Australia's competition watchdog urged the government to curb LNG exports after warning on Aug. 1 that the country's eastern states would face a gas supply shortfall in 2023 if the three east coast LNG plants exported all of their uncontracted gas.

Origin Energy is a co-owner of APLNG, one of three LNG plants on the east coast. Calabria's comments matched those of rival Santos on Wednesday, which also said it does not expect the government will need to trigger export curbs. (Reporting by Sonali Paul; Editing by Muralikumar Anantharaman)