Ten years after they were arrested for attempting to smuggle drugs out of Indonesia, Andrew Chan and Myuran Sukumaran have been told they will be executed as soon as Tuesday.

On Saturday, the Bali Nine ringleaders received formal notification from Indonesian authorities that they will soon be shot for trying to export more than eight kilograms of heroin to Australia.

The two men were arrested at Denpasar airport in April 2005 and sentenced in 2006 to execution by firing squad.

• Execution notices given to Chan, Sukumaran
• Families make emotional pleas for Bali duo
 • We won’t give up on Bali duo

The pair have been refused clemency by Indonesian president Joko Widodo as part of a hardline stance on the death penalty for convicted drug criminals.

But their families say the executions would be a grave injustice.

After spending some of his final hours with his brother, Chinthu Sukumaran said his brother’s last wish was to paint for as long as possible.

“He’s found peace with what may happen but he and we all feel that this is a grave injustice and it did not have to be this way and it still doesn’t have to be this way,” he told reporters.

The Bali Nine pair was told on Saturday they will be executed as soon as Tuesday, a moment preserved by Sukumaran who signed one of three self-portraits “72 hours just started”.

Fateful painting by Myuran Sukumaran. Photo: AAP

Their lawyer Julian McMahon took a fourth more disturbing self portrait from his cell on Sunday, depicting the artist shot through the heart.

The pair received a briefing from their lawyers on the intentions of Indonesian authorities during a visit to the prison island of Nusakambangan.

On Sunday, siblings, friends and other relatives of the two Australians have gone to the prison island Nusakambangan, along with consular officials.

Sunday is not a regular visiting day at the prison island and it is believed that rules governing family visits are more liberal within the final days.

Sukumaran’s sister issued an emotional plea for his life to be spared, appearing in a YouTube video clutching a photograph of her brother as a young boy wearing a school uniform.

Andrew Chan’s mother Helen, and the pair’s lawyer Julian McMahon. Photo: AAP

“My brother made a mistake 10 years ago and he’s paid for this mistake every single day since then,” Brintha Sukumaran said.

“My brother is now a good man and after 10 years in prison, he has taught so many Indonesian prisoners about art and about how to live outside in the world and have a good and productive life

“From the bottom of my heart, please President Widodo have mercy on my brother … change punishment for humanity.”

Sukumaran’s reference to the 72 hours relates to a process Indonesia has laid out for itself after an international backlash to its resumption of executions in January.

The procedure outlined by Indonesia’s attorney-general Muhammad Prasetyo and repeated by spokesman Tony Spontana is to give a minimum of 72 hours’ notice before the next 10 criminals face the firing squads.

Bishop continues to seek clemency

Australia’s Foreign Minister Julie Bishop concluded that the executions of Chan and Sukumaran would be “scheduled imminently”.

Ms Bishop added that she had spoken to Sukumaran’s mother, Raji, “and assured her the Government would continue to seek clemency from Indonesian president (Joko) Widodo for both men”.

She has also spoken with her Indonesian counterpart and stressed the need for all legal processes to be carried out before action is taken.

Labor’s foreign affairs spokeswoman Tanya Plibersek said it was vital high-level contact with Indonesia’s leaders continued.

“It’s absolutely vital that the Prime Minister and Foreign Minister make every effort to contact their counterparts,” she said.

Earlier on Saturday, Indonesian government officials called consular teams for the foreigners due to be executed to explain rules and processes, including how death row prisoners’ “last requests” would be met.

On Monday, a legal challenge by the Indonesian death row prisoner Zainal Abidin is set to be confirmed as lost, giving the Indonesian government more reason to step up preparations for the group of 10.

But predicting the timing remains difficult.

Although the prisoners have been told they will be executed and that “the soonest” will be in three days, Indonesian officials stress that the “72-hour rule” is only a minimum and does not prevent the government waiting longer if it chooses.

—with AAP, ABC