Australians Andrew Chan and Myuran Sukumaran will not be transferred from Bali for their planned executions this week, partly because the island prison they were to be sent to has run out of death row isolation cells, Indonesian officials say.

On Monday authorities were saying that Chan and Sukumaran would be taken to the execution venue, Nusa Kambangan island prison off Java, as soon as Wednesday morning.

But now the plans to move them out of Bali's Kerobokan prison are on hold, partly so they can spend more time with their families.

"This is a response to the Australian Government and the families to give them more time to be with inmates," said attorney-general spokesman Tony Spontana.

"Secondly, apparently, after checking the location there are technical obstacles which we have to solve before we move the prisoners."

Mr Spontana said there were not enough isolation cells ready at the prison off Java to hold the five inmates, including Chan and Sukumaran, who are expected to be executed.

The attorney-general's office will not say when they will be moved, but the delay buys them some precious time as their lawyers prepare their last legal challenge against execution.

The two men are on death row for attempting to smuggle drugs to Australia in 2005 as part of the so-called Bali Nine.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 46 seconds 4 m 46 s Indonesia postpones transfer of Chan and Sukumaran ( George Roberts ) Download 8.7 MB

Lawyers for Chan and Sukumaran said on Tuesday moving the pair to another prison in preparation for their executions would be an injustice.

Chan and Sukumaran were recently denied presidential pardons, despite prison officials supporting their clemency bids.

The pair's lead lawyer, Todong Mulya Lubis, has been summoned to a court next week over a claim that president Joko Widodo has not followed the rules in rejecting the pair's plea for clemency.

He said the court hearing showed that all legal avenues had not yet been tested, and was concerned that if the men were moved out of Bali later this week as expected, it would make it hard to reverse the process.

"They cannot transfer, they cannot move Chan and Sukumaran, let alone kill them, while the legal process is going on," Dr Lubis said.

"It's hard to reverse the process once they are moved to Nusa Kembangan."

Dr Lubis also said the legal system should investigate allegations around some of the judges who granted the death penalty.

Earlier another member of the legal team, Peter Morrissey SC, said any moves by the attorney-general to execute Chan and Sukumaran should not proceed as long as the court hearing was underway.

"What we've got in Indonesia right now is there's a live court proceeding but the attorney-general keeps threatening to move them and to proceed with the execution," Mr Morrissey told ABC News Breakfast.

"So it's as if the courts on the one hand have got a live case but on the other hand the government's proceeding to execute. That's just not the rule of law.

"If they give it a proper hearing they will probably never be executed because [Indonesia] might be persuaded."

Execution preparations continue despite legal team's objections

Indonesian foreign affairs staff have briefed officials from diplomatic missions, including a representative from Australia, about what the inmates' families can expect in the lead-up to the planned executions.

The pair are due to be moved to the high security prison on Nusa Kambangan Island, where they will face execution by firing squad. ( AAP: Darma Semito )

According to Australian barrister Michael O'Connell, who has worked on the case since 2007, Chan and Sukumaran are handling the uncertainty and looming timeline well.

"[They are] composed and dignified in the way they are dealing with these very trying times," Mr O'Connell said.

Bali's chief prosecutor, Momock Bambang Samiarso, is in charge of organising the pair's transfer to Nusa Kambangan island, off Java, where they are to be executed.

"We're going to use air transport. We are still discussing the details but we're going to use air transport for sure," he said.

"We will inform you when we [know] the time ... it's not going to happen today or tomorrow, but within the week."

Bali's police chief, Albertus Julius Benny Mokalu, said Indonesia's elite police squad, the Mobile Brigade, would help provide security for the transfers.

"We will work together with related institutions including the military in regards to security for prisoner transfer, so it will happen smoothly and securely," he said.

Sorry, this video has expired Lawyers for Bali Nine pair remain optimistic

The firing squad will be made up of local police.

Australian Cabinet Minister Malcolm Turnbull this morning made another direct appeal to the Indonesian government to spare Chan and Sukumaran from the firing squad.

"I think it would be a sign of great strength on the part of the Indonesian president to spare the lives of these two men," he said.

"I know a lot of people are saying it would be weak of President Jokowi not to proceed with the executions, but I think it would be a sign of great strength, of great love, recognising that Indonesia is a strong, loving country that does not have to kill these two men.

"Yes, they committed crimes, but the strongest love is when it is extended to those who least deserve it."

Mr Morrissey also said the Indonesian government could show "toughness" by granting clemency.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 4 minutes 11 seconds 4 m 11 s Australian Government has done 'all it can', Indonesian law expert says Download 7.7 MB

"Showing toughness is showing restraint when your natural instinct is not to do it, when you've got people who are convicted of drug dealing and you feel like smashing them," he said.

"It's good and it's strong to show restraint and the Indonesians are wonderful at getting restraint for their own people abroad.

"They persuaded the Saudis to spare Indonesian foreign workers and we're hoping they get some perspective from that and that they're able to consider sparing some of the foreigners in their own land who have transgressed."