The Coordinating Ministry of Maritime and Investment Affairs said on Thursday an export ban implemented on January 1 had been eased for miners that had met a requirement to sell a portion of their output for local power generation after the state utility procured enough coal at power stations to ensure 15 days of operations.

"I request that this is supervised closely so this also becomes a moment for us to improve domestic governance," coordinating minister Luhut Pandjaitan said in a statement.

Sending shockwaves through global energy markets, Indonesia set the export ban after state power company Perusahaan Listrik Negara (PLN) reported critically low coal stocks at power plants that left Indonesia on the brink of widespread power outages.

Indonesian authorities blamed the coal supply crisis on miners failing to meet a so-called Domestic Market Obligation (DMO), requiring them to sell 25 per cent% of output to local buyers with a price cap at $US70 ($A96) per tonne for power plants.

The government has been lobbied by coal miners and also some of its biggest buyers including Japan and South Korea to ease the export ban.

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

The ministry said that mining companies that had met their sales contract with PLN and 100 per cent of their DMO requirements for 2021 would now be allowed to begin exporting.

Miners that had not fulfilled their PLN contracts and DMO would face fines, it said.

Australian Associated Press