JAKARTA: Indonesian authorities have yet to issue papers to allow 14 coal vessels to depart, a senior official said on Wednesday, as the government prepared to assess whether to further ease an export ban in the world's biggest shipper of thermal coal.

The suspension was implemented on Jan. 1 to avoid widespread domestic power outages, after state utility Perusahaan Listrik Negara (PLN) reported critically low coal stockpiles, amid complaints that miners were not fulfilling commitments to supply fuel to the firm. 

The ban has concerned major coal importers, like Japan, South Korea and the Philippines, which fear economic disruption at home.

There are currently about 120 vessels either loading or waiting to load off Indonesian's coal ports in Kalimantan on the island of Borneo, according to Refinitiv Eikon data.

All 14 loaded coal vessels that were given the go ahead on Monday to depart once verified by authorities were still awaiting formal approval early on Wednesday, Transportation Ministry official Mugen Suprihatin Sartoto told Reuters.

The government will conduct a review of the ban on Wednesday and has said any resumption would be gradual, so it can assess how restarting exports might affect miners' compliance with the so-called Domestic Market Obligation (DMO) rules.

Under DMO rules, miners must sell 25% of their output to the local market, capped at $70 per tonne for domestic power plants.

During a panel discussion on MetroTV late on Tuesday, energy ministry senior official Ridwan Djamaludin said the ban remains in effect until Jan. 31, unless lifted earlier.

"What we are waiting for now is the delivery of coal to the power plants," Ridwan said.

In the same discussion, PLN chief executive Darmawan Prasodjo said the company has secured 16.2 million tonnes of coal commitments.

PLN in a statement on Wednesday said it was working to ensure commitments secured during the export ban were delivered on time.

(Reporting by Bernadette Christina Munthe; Writing by Fransiska Nangoy; Editing by Martin Petty) ((Fransiska.Nangoy@thomsonreuters.com;))