The amendment, if implemented, will be the first such change on coal royalties in three years.

Energy and Mineral Resources ministry mineral and coal program supervision director Sujatmiko was quoted by Bloomberg as saying: "We’re revising a 2012 regulation on mining-royalty tariffs.

"We target to impose new tariffs not later than April so that there will be plenty of time to meet higher revenue target."

The government has also been asked to raise non-tax revenue from coal and metals mining to IDR52.2trn ($4.1bn) from IDR35trn in 2014.

Under the proposed regulation, royalties of 7%, 9% and 13.5% will be paid for coal with heating value fewer than 5,100 kilocalories, 5,100 to 6,100 kilocalories and more than 6,100 kilocalories.

Sujatmiko said that the tariffs will be applicable for miners holding a IUP mining business license. Such companies account for 25% of coal production estimated at 425 million tons for 2015.

Meanwhile, miners managing contracts of works will be required to pay 13.5% royalty.

The government will suggest building metal smelters to boost metal export revenues, Sujatmiko added.

Indonesian coal exports this year could remain same as in 2014 at 350 million tons, compared to 300 million tons estimated previously, Reuters reported.

Indonesian Coal Mining Association chairman Bob Kamandanu told the news agency that the rise in export volumes will be facilitated by major producers in the region.