JAKARTA (REUTERS) - Australia needs to show proof of alleged corruption in the trial of two Australians on death row before Indonesia's government will investigate, the foreign ministry said, questioning why concerns were being only raised now instead of 10 years ago.

Mr Armanatha Nasir, a spokesman for Indonesia's Foreign Ministry, said Australian's Myuran Sukumaran and Andrew Chan have been given all the legal avenues to challenge their death sentences.

Indonesia's Judicial Commission also said it would look into reports alleging that corruption had tainted the trial, but said its findings would have no bearing on their cases. "We have received a report on that, we have it in our file now, but we have not yet made any decision," Commissioner Taufiqqurahman Syahuri told Reuters. "But even if it is proven that the judge violated ethical codes, it won't affect the court's earlier decision. We cannot annul a decision from a court, such a thing can only be done by a higher court. What has been decided is final. The Judicial Commission can punish the judge, but ethical and legal matters are different."

The two are among nine drug convicts due to be executed by firing squad as early as Tuesday.