Over the past month, there have been several media reports that Japan is seeking WTO intervention after Indonesia, one of the world's top nickel ore producers, announced a raft of new mining regulations, including a ban on some unprocessed metals exports from May.

Japan is a major importer of Indonesian nickel and thermal coal.

"We have not under any circumstances suggested to the Indonesian government that Japan is planning to file a complaint to the WTO during our bilateral talks on the 2014 export restrictions plan," said an official at Japan's trade ministry who declined to be identified because of ministry regulations.

"We are seeking solutions to the issue through measures other than the WTO route," the official said, adding that if Indonesia's export ban is found to contravene WTO rules, Japan may consider a complaint.

Deddy Saleh, director general of foreign trade at Indonesia's Trade Ministry, also said talk of a Japanese complaint to the WTO was premature.

The Indonesian government in May ordered all miners to submit plans to build local smelters or process ore domestically by 2014, when a total ban on raw mineral exports kicks in. It also imposed a tax of 20 percent on ore exports.