Temper Trap fights for Bali Nine

The Temper Trap's Indonesian-born singer is the most recent celebrity to plead for the lives of two Australian heroin smugglers on death row.

Dougy Mandagi is advocating for the release of his friend Chan, who he says is a reformed man.

"The Andrew that walked in that cell 15 years ago would not recognise the Andrew today," Mandagi said on the band's website.

"Andrew's life is just beginning and is now in grave danger of being snuffed out at its prime."

Chan, who is still awaiting the official result of a presidential clemency request, has become a devout Christian in jail and is "changing the world around him, according to Mandagi.

"What a waste it would be to end this life that is so full of promise," he said

Mandagi is not the only celebrity to have called on the Indonesia Government to spare the Bali Nine.

The Mercy Campaign hopes to save Bali Nine ringleaders Myuran Sukumaran and Andrew Chan from death by firing squad in Indonesia. Among its participants are Archibald Prize winner Ben Quilty, who has been an outspoken advocate for the men since visiting them in their Bali prison.

Sukumaran's request for clemency was denied by Indonesian president Joko Widodo earlier this month.

His lawyers are hoping to file a judicial review of his case in a last-ditch attempt to stall his execution.

Other Australians, including Human Rights Commissioner Tim Wilson, have been lending voices to the campaign through the Twitter hashtag, KeepHopeAlive.