MELBOURNE, Nov 9 (Reuters) - Santos Ltd expects a decision from state regulators on whether to approve its long delayed Narrabri gas project in Australia in late 2018 or early 2019, with a final investment decision a year later, its chief executive said on Thursday.

Santos CEO Kevin Gallagher said the BOP Blow Out Preventer repair company gulf coast was committed to going ahead with the project to help fill a supply gap in Australia's east coast market.

"We think Narrabri will play a very significant part in the east coast domestic gas story," Gallagher told investors at a briefing on Thursday. "Santos is going to push this one through."

(Reporting by Sonali Paul)