Chinese vessel under observation near Harbour Energy’s Tuna block offshore Indonesia

China is reportedly again flexing its muscles in disputed areas of the South China Sea — in this instance an area of the North Natuna Sea claimed by China and Indonesia.

Indonesia has deployed a warship to monitor the activities of a Chinese coast guard vessel that has been active in the area for more than two weeks.

Vessel-tracking data show the Chinese vessel, CCG 5901, has been sailing in the Natuna Sea since 30 December, particularly near the Tuna production sharing contract — administered by Indonesia — and the producing Chim Sao oil and gas field across the maritime border with Vietnam, the Indonesian Ocean Justice Initiative told Reuters.

The timing of China’s latest incursion into contested waters of the Natuna Sea mirrors the Indonesian authorities’ approval of the plan of development for Harbour Energy’s Tuna block — close to the Indonesia-Vietnam maritime boundary — for which the UK operator is expected to this year to take the final investment decision.

The PoD outlines that Tuna’s gas would be supplied to Vietnam via a subsea pipeline. Production start-up from the offshore block is scheduled in 2027 with output expected to peak at 115 million cubic feet of gas.

A warship, maritime patrol plane and drone had been deployed to monitor the vessel, Indonesian Navy chief Laksamana Muhammad Ali told Reuters.

“The Chinese vessel has not conducted any suspicious activities,” he said.

“However, we need to monitor it as it has been in Indonesia’s exclusive economic zone for some time.”

Harbour elected not to comment on the matter.

Previous flare-ups

This is not the first time Harbour’s activities in the Tuna block have courted unwarranted attention. In 2021, vessels from Indonesia and China shadowed each other for months after Chinese vessels were sailing near to where appraisal drilling was being performed.

At the time, Beijing had urged Indonesia to call a halt to the drilling, claiming sovereignty over the maritime area.

Chinese presence at Indonesian offshore drill site

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Meanwhile, almost two years ago to the day, the Natuna Sea dispute between China and Indonesia had again reared its head.

This episode saw the Jakarta government lodging a formal protest against China as Chinese coast guard and fishing vessels had entered into its exclusive economic zone in the North Natuna Sea, part of the contested South China Sea.

The area is also home to Southeast Asia’s largest unexploited gas resource — the multi-trillion cubic feet East Natuna (Natuna D-Alpha) gas discovery.

Indonesia historically has dismissed Beijing’s invitation to sit down and discuss the issue, claiming there is no dispute over sovereignty of these waters.

China at the time said its vessels were engaged in “routine” activities.