Lawyers for Andrew Chan and Myuran Sukumaran will challenge the presidential decree that denied them clemency in a Jakarta court, if they can clear the jurisdictional hurdles that tripped up the only other case of its kind.
Authorities say it's "very likely" the Bali Nine duo will this week be relocated to the island where Indonesia plans to execute them.
Their lawyers will today front Indonesia's State Administrative Court to challenge President Joko Widodo's decision to deny them clemency because they were death row drug offenders, without considering their circumstances.
It's a rare challenge, and the only one like it was brought by an anti-drugs group against the decision to grant clemency to another Australian drug smuggler, Schapelle Corby.
It failed when the presidential decree was deemed outside the realm of the administrative court, and Corby is now free on parole.
Chan and Sukumaran were to be transferred from their Bali jail cells to Nusakambangan penal island last week, but it was found to have inadequate isolation cells.
Indonesian Attorney General HM Prasetyo yesterday said preparations were now "about 80 per cent" complete.
Construction materials have been arriving on the island and a jail official has said there are orders to accelerate the works for completion within days.
The Indonesian Military has also made plans to secure the transfer of the men from Bali to central Java.
A squadron of Sukhoi jets has arrived at Bali's Ngurah Rai Airport, where air force commander Sugiharto Prapto said they were yet to receive orders related to the Bali Nine pair, but were there for seven days if needed.
If they use a charter plane, we're ready to secure it so that the operation can be implemented safely and smoothly, he said.
Indonesian news agency Antara reports Indonesian Military commander General Moeldoko has given orders for a Hercules aircraft to transport the men to Nusakambangan, guarded by the jets.
"Don't try to disrupt the executions by any means. The military is prepared. Don't try to introduce a scenario that will disrupt the executions," Gen Moeldoko reportedly said.
Meanwhile Mr Joko appears to be keen to let tensions with Australia over Chan and Sukumaran simmer down.
Asked about Prime Minister Tony Abbott drawing a link between tsunami aid to Indonesia and the death sentences on Monday, Mr Joko reportedly said: "There's already been clarification. Don't you heat this up."
Asked if it would affect plans to execute the convicted drug smugglers, Mr Joko said: "No, that's our sovereign law", as quoted by Indonesian news website detik.com.
Tensions between Canberra and Jakarta boiled over last week after Jakarta perceived Mr Abbott's comments as threats and warned that "no one responds well to threats".
