Bali Nine
Chintu Sukumaran, brother of Australian death row prisoner Myuran Sukumaran, carries a self-portrait painted by Myuran Sukumaran at Wijayapura port in Cilacap, Central Java, Indonesia, April 28, 2015.Reuters

Indonesia said the execution of nine drug traffickers would go ahead this week, rebuffing last-minute appeals from Australia and the Philippines to spare their nationals and ignoring a decision by the Constitutional Court to hear a final challenge.

Australia began the day with a plea for a stay in the execution of Myuran Sukumaran and Andrew Chan, saying reports that their trial had been tainted by corruption needed to be investigated.

Foreign Minister Julie Bishop said allegations that judges requested money to commute the death sentences were "very serious" and called into question the integrity of the process.

Indonesian President Joko Widodo brushed that off, telling reporters that such concerns should have been conveyed a decade ago when the case when through the courts.

The prospect of a reprieve for the pair emerged later, when their lawyer said that the Constitutional Court would hear another challenge on May 12.

But Attorney General spokesman Tony Spontana said the executions would not be delayed by the court's decision to hear their case and insisted that the execution of all nine on death row would proceed this week.

The other seven who were informed at the weekend that they would face the firing squad as early as Tuesday are four Nigerians, an Indonesian, a Brazilian and a Filipina.

Philippines President Benigno Aquino appealed to Widodo at a summit of Southeast Asian nations to spare the Filipina, a mother-of-two who says she was duped into carrying drugs into Indonesia.

Widodo said he was sympathetic and would consider the plea, but later Indonesia's Attorney General said there would be no clemency for Mary Jane Veloso.

Indonesia has harsh punishments for drug crimes and resumed executions in 2013 after a five-year gap.

Widodo has been unbending in his hard line on traffickers and his refusal to grant foreigners on death row clemency has strained relations with several countries, particularly neighbor Australia.

Australia-Indonesia relations have been tested in recent years by disputes over people smuggling and spying. In late 2013 Indonesia recalled its envoy and froze military and intelligence cooperation over reports that Canberra had spied on top Indonesian officials, including the former president's wife.

CORRUPTION ALLEGATION

Widodo's steadfastness on the executions, which has strong public support at home, stands in contrast to a series of policy flip-flops since he took office six months ago. Palace insiders and government officials portray him as sometimes out of his depth and struggling to get around entrenched vested interests.

Chan and Sukumaran, ringleaders of the so-called Bali Nine, were arrested at the main airport on the holiday island of Bali in 2005 for trying to smuggle 8 kg (17.6 lb) of heroin to Australia. The other members of the gang, all Australians, have been jailed for between 18 years and life in Indonesia.

Bali-based lawyer Muhammad Rifan told the Sydney Morning Herald that he had agreed to pay judges in the cases of the two men more than A$130,000 ($101,647) to give them a prison term of less than 20 years.

Rifan said the deal fell through when the judges told him they had been ordered by senior legal and government members in Jakarta to impose a death penalty and he did not have enough money to meet a revised, higher demand for a lighter sentence.

"It's a matter for Indonesia's Judicial Commission to investigate these matters and that underlines why we continue to request Indonesia to allow the Judicial Commission to finalize its review," Bishop told reporters.

Rifan could not be reached for comment.

Indonesia's Judicial Commission said it would look into reports alleging corruption but said its findings would have no bearing on their cases.

"Even if it is proven that the judge violated ethical codes, it won't affect the court's earlier decision," Commissioner Taufiqqurahman Syahuri told Reuters.

"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."

At the high-security jail on Nusakambangan Island in Java, where the nine are due to be executed, Australian Chan married his Indonesian girlfriend Febyanti in prison on Monday. A small group of family and friends attended the ceremony.

"It's tough times but it's happy times at the same time," Michael Chan, Andrew's brother, told reporters on the mainland.

"We just hope that the president somewhere will find some compassion and mercy for these two, this young couple so they can carry on with their lives."