The routine maintenance, which typically takes a month, is not expected to affect exports, said Didik Sasongko Widi, President Director of Badak NGL, which operates Bontang.

Badak operates five trains at Bontang, including the one on maintenance and one that is idled or on standby mode.

Three other trains have been permanently shut due to declining supply from Indonesia's Mahakam gas block.

The maintenance could help boost Asian spot LNG prices <LNG-AS> as it coincides with an outage at one of three trains at Chevron Corp's Gorgon LNG plant in Australia, trade sources said.

Spot LNG prices fell to an eight-month low last week due to a mild winter in East Asia.