A Muslim psychologist who once said teenagers arrested on terrorism charges were just 'acting out' was allegedly aware of an Australian extremist heading to join IS.

Psychologist, Hanan Dover, from Punchbowl in Sydney's west, conversed with extremist preacher Robert 'Musa' Cerantonio over the phone before he was caught leaving Australia by a fishing boat.

The conversations which were intercepted by Australian Federal Police allegedly reveal discussions between the pair suggesting he wanted to leave to join the terrorist group, reported The Daily Telegraph.

Sydney psychologist, Hanan Dover (left) allegedly knew Australian extremist Robert 'Musa' Cerantonio (right) was leaving the country to try and join IS

'The only advice I'll give you, I thought about this last night, is the future that you want, if you are successful the people that you leave behind they will be under surveillance and just think about that,' Ms Dover allegedly said in one of the intercepted conversations.

'I'll speak to you soon. My advice to you is to shhh ...' Cerantonio allegedly said.

'Yeah, I just thought about that now. I know. I'm an idiot,' Ms Dover allegedly replied.

Conversations between the pair over a period of five months were intercepted by the AFP

Cerantonio is accused of confiding in Ms Dover during which he explained he had not heard from his 'teacher' within IS

The conversation which were tendered in court for Cerantonio’s case, spanned across five months.

Last November Cerantonio allegedly spoke to Ms Dover's daughter to suggest she should live in a country with sharia law.

Cerantonio is also accused of confiding in Ms Dover during which he explained he had not heard from his teacher with the Islamic State because his vicinity was being bombed.

A week later he allegedly confided once again with Ms Dover explaining his teacher was alive but two friends were martyred.

It is believed Ms Dover tried to visit Cerantonio while he was in custody in Cairns

Musa Cerantonio was caught during the first leg of their trip, which saw them drive from Melbourne to Cairns with a small tin boat attached to their car

Notorious Islamic preacher Musa Cerantonio, was one of the five men arrested in May after their plot to sail from Cairns to Indonesia before fleeing to Syria to join ISIS.

They were caught during the first leg of their trip, which saw them drive from Melbourne to Cairns with a small tin boat attached to their car.

Cerantonio is known for posting videos online to urge others to join 'jihad' in Iraq and Syria.

In 2014 the radical preacher was arrested in the Philippines and deported back to Melbourne, and last year his passport was cancelled.

It is believed Ms Dover tried to visit Cerantonio while he was in custody in Cairns.