A well-known radical Islamic preacher and a 21-year-old who wanted to renounce his Australian citizenship were among five Melbourne men arrested in Far North Queensland before they could sail to Indonesia, then travel to Syria, according to police.

Musa Cerantonio - an Islamic convert and preacher described by the International Centre for the Study of Radicalisation as "an outspoken cheerleader for ISIS" - as well as Shayden Thorne, the brother of firebrand self-styled preacher Junaid Thorne were among the five Melbourne men arrested north of Cairns on Tuesday.

Kadir Kaya - who openly declared that he hated Australia and wanted to leave on national radio little more than six months ago - was another of the men on the bizarre trip, which police will allege was designed to give them passage to Indonesia, where they would link with smuggling networks who could ferry them to the Middle-East.

Little is known about the other two members of the party: Antonio Granata, 25, who is understood to have family in Melbourne's west, and another man who could not be identified. All the men previously had their passports cancelled.

Mr Kaya, 21, told Radio 3AW in October last year that he wanted to live in Turkey, but couldn't leave Australia as his Turkish passport had been cancelled and his application for an adult Australian passport had been refused.

He had been on a watch list since early-2014, he said during the interview, and claimed he wanted to join the Turkish military to fight against Islamic State.

As a teenager, Mr Kaya had been a member of Copperfield College's youth parliament, and was photographed on the steps of State Parliament with then Minister for Youth Affairs Ryan Smith.

He lived near the school in Cairnlea in Melbourne's outer-west.

"'If I'm such a threat then you wouldn't want me here," he said in the radio interview.

"You don't like me, I don't like you and that's the reality here. I've been trying to tell them 'let me out'. They've basically kept me in prison…an open air prison."

Police say the group, aged from 21 to 33, towed the boat, which is believed to have been bought in Bendigo, from Victoria to Queensland in a sedan that was ill-suited to the seven-metre vessel and trailer. Police followed them much of the way.

The men were on terror watch lists and police, monitoring their activities and fearing they would drown in the treacherous waters, thwarted their scheme before they could set sail from Cape York.

Victoria Police Deputy Commissioner Shane Patton said the incident should not be downplayed.

"I know there'd be people sitting at home saying 'why don't you simply just let them go and take their chance in the waves and fighting in Syria'.

"We can't do that. 

"We can't allow Australians to leave Australia and support terrorism."

Mr Patton said eight warrants were executed in Melbourne and Queensland on Tuesday afternoon.

AFP Assistant Commissioner Neil Gaughan said the men were "extremely committed in their venture and attempt to leave the country" but were not involved in any domestic attack plans or threats.

Attorney-General George Brandis confirmed that it was the first time suspected extremists had attempted to leave Australia by boat.

He said the men had tried to leave by boat to "circumvent the effect of the passport cancellation".

Mr Cerantonio, who grew up as Robert in a Catholic family of Italian heritage in Melbourne's west, is understood to have gradually increased his sphere of influence in the past year.

He kept a low profile immediately after returning to Melbourne in 2014 after his Australian passport was cancelled while he was in the Philippines.

Mr Cerantonio is believed to have started hosting weekly Islamic classes in Caroline Springs in mid-2015, which focussed on "the essentials of Islam" and adherence to the Koran, but it understood the classes were cancelled by October.

In January, he made what was believed to be his first online posting since returning to Australia, when he uploaded a video to Facebook condemning homosexuals.

Mr Cerantonio's links to Junaid Thorne, who similarly raised the ire of authorities with extreme online posts, have previously been documented.

The brothers lived in Western Australia before moving to Saudi Arabia in the 1990s.