It is expected to begin in the third quarter of 2021 versus at initial target of the third quarter of 2020, he said.

A number of natural disasters across Indonesia have delayed shipments of construction material needed in Tangguh, he said, adding that financial difficulty faced by one contractor had also hampered progress.

BP Indonesia head Moektianto Soeryowibowo confirmed to Reuters there had been an issue with a contractor and said the company was in discussions with its partners, the contractor consortium, and the government on how to best mitigate the impact on costs and schedule.

"Work on the onshore engineering, procurement and construction being carried out by the Chiyoda-Saipem-Tripatra-Suluh Ardhi Engineering (CSTS) consortium is being impacted by several factors and requires additional work," Soeryowibowo said by text message.

He noted that the Tangguh Train 3 project, which currently has 7,000 workers on site, "will add a production capacity of 3.8 million tons of LNG per year (mtpa), bringing Tangguh's plant total capacity to 11.4 mtpa."

(Reporting by Wilda Asmarini; writing by Fransiska Nangoy; editing by Jason Neely)