"We are following Newcastle index pricing for importing coal," said Nasrul Hamid.

"Now that we are getting a discount on the pricing for other coal plants, such as the Payra power plant, we want to open the door for negotiations with Adani, too. We have sent them a letter to discuss the issue."

Adani Power did not immediately respond to a request for comment from Reuters.

(Reporting by Ruma Paul, writing by Shivam Patel)