A former Islamic State group commander who allegedly plotted to blow up an Etihad flight departing Sydney could be executed within 40 days.

Key points: The AFP alleges a 48-year-old man directed his Sydney-based brothers to plant a bomb on an Etihad flight to Abu Dhabi

The AFP alleges a 48-year-old man directed his Sydney-based brothers to plant a bomb on an Etihad flight to Abu Dhabi They are accused of planting the device on an unwitting family member

They are accused of planting the device on an unwitting family member Lebanese authorities allege the plot was only foiled when airline staff told the man his bags were overweight

Tarek Khayat was sentenced by Alrasafah Central Criminal Court in Baghdad this week over his role as an Islamic State (IS) commander in Iraq.

The 48-year-old Lebanese citizen was arrested earlier this year in the former IS group stronghold of Raqqa.

He was not charged over the plane plot.

The Iraqi court has confirmed he has 10 days to appeal against the sentence.

Appeals by convicted IS fighters rarely, if ever, succeed and execution by hanging can follow as soon as 30 days after the date of appeal.

The Australian Federal Police allege 48-year-old Khayat directed his Sydney-based brothers to plant a bomb last July on an Etihad flight from Sydney to Abu Dhabi.

Tarek Khayat (pictured at rear in this family photo) is alleged to have directed his two brothers to plant the bomb in a third brother's luggage. ( Supplied )

Three of Khayat's brothers are in custody over the plane bomb plot. Khaled and Mahmoud Khayat will face trial in the NSW Supreme Court next year.

They are accused of planting a bomb in the luggage of an unwitting family member — a fourth brother, Amer Khayat.

Lebanese authorities allege the plot was foiled only when Etihad check-in staff told Amer Khayat that his bags were overweight.

The alleged bomb, apparently hidden inside a meat grinder, was removed and Amer Khayat continued his journey to Beirut.

Amer Khayat poses for a mugshot before facing court in Lebanon. ( Supplied )

The AFP said Amer Khayat had nothing to do with the plot. He was arrested by Lebanese authorities 11 days after he arrived and has been in custody since. He has faced several hearings before a military tribunal which is trying to work out his involvement in the alleged plot.

Amer Khayat said he knows nothing about ISIS and came to Lebanon to visit his family.

Waled Khayat told the ABC last month he does not want to talk about his brother Tarek. ( ABC News: Aaron Hollett )

Last month the ABC spoke to the Khayat family in Tripoli, who said they were in shock over the bomb allegations. Another brother, Waled Khayat, said Tarek had caused great difficulty for his family.

"I don't want to talk about Tarek," he said last month. "I don't care. He chose his own path.

"Of course Tarek's situation had a terrible impact on our family. My sons have grown up now. I fear that they could be arrested because of him."

The ABC has previously reported that before moving to Syria with his wife and five children in 2014, Tarek Khayat was a senior Islamic State commander in the northern Lebanese city of Tripoli.

He was wanted by Lebanon for allegedly trying to set up an IS emirate in the country's north and for leading his followers in battles against the Lebanese Army in Tripoli in 2014, shortly before he fled to Syria.