Even as Indonesia delayed the planned executions of two Australians on death row for drug dealings, Australian foreign minister Julie Bishop has raised hopes of sparing their lives by offering a prisoner swap.

Early reports suggest Indonesia did not accept the prisoner swap offer.

Speaking at a vigil for the Bali Nine duo outside Canberra's Parliament House on 5 March, Bishop again asked Indonesia to show mercy to the two men.

Confirming that she had brought up the idea of a prisoner swap with her Indonesian counterpart Retno Marsudi on Tuesday (3 March) evening, Bishop said the details were not discussed.

Should the swap occur, Indonesia and Australia could sign a memorandum of understanding, she said.

"I didn't go into any specific detail but I did note there were Australian prisoners in Jakarta and there were Indonesian prisoners in Australia and that we should explore some opportunity, a prison swap, a transfer, whether that could be done under Indonesian law," she said of the phone call.

Three Indonesians are in prison in Australia over their role in a 1998 drug bust.

Kristito Mandagi, Saud Siregar and Ismunandar were part of a crew on a boat carrying 390 kilograms of street-ready drugs and a loaded Glock pistol to a beach near Port Macquarie, NSW.

The drug haul was 47 times bigger than Chan and Sukumaran's, reports ABC.

The drugs, of which the pure heroin component weighed 252.3 kilograms, were worth $600m on the street.

Prime Minister Tony Abbott has told reporters he was seeking a "final call" with President Widodo.

"I've put in a request, I can't guarantee the request will be met, but I've put in a request because the government and the people of Indonesia need to know that this is important to us," he said.

"These men have become crime fighters and they are assets to Indonesia in the fight against drug crime and when you've got an asset you don't destroy it."

Indonesian President Joko Widodo said he had a constitutional responsibility to follow through with the executions ordered by the court.

He said the plea for clemency was rejected after a careful study of the case and the details of drugs distributed by the duo.

However, he said the planned executions would not take place this week.

Pastor Jeff Hammond, who has counselled Chan in prison for the past four years, said the prisoner had not given up hope when he last saw him three days ago.

Chan and Sukumaran have been transferred to isolation cells on Nusakambangan island prison in Central Java to await news about the timing of their executions.

The Australian pair is among a group of 11 prisoners who have recently been approved for execution by the Indonesian government.

The list includes prisoners from France, Ghana, Brazil, Nigeria, the Philippines and Indonesia.