Australian Opposition Leader Bill Shorten has urged Australians travelling overseas to exercise a high level of caution, following "deeply concerning" reports of a suspected Isis (Islamic State) member plotting to attack today's Anzac commemorations at Gallipoli.
The Labor leader said he's requested security briefings which will be coming within hours.
"This world should have no tolerance for violent extremism - violent Islamist extremism or any other quarter," he told reporters. "But what we can't do is let it discourage the marvellous tradition of young Australians travelling to the battlefields where Australians have fallen in previous conflicts.
"We should be proud of our identity as Australians and our history, and we should learn about the sacrifice."
"We've always got to maintain a high level of caution," he said, noting the recent terror bombings in Sri Lanka as an example. "But I for one love that so many young Australians in particular are coming to dawn services in numbers unseen."
A suspected Isis member has been arrested in Turkey over a plot to attack today's Anzac commemorations at Gallipoli which will be attended by thousands of Australians and New Zealanders.
The arrested man, from Syria, was taken into custody in Tekirdag, a province close to the Gallipoli Peninsula, police said.
Security sources told the ABC the attack was planned in retaliation for the Christchurch mosque attacks.
Local media named the man as Abdulkerim Hilef, 25, and released a blurred photo of him.
The arrest followed a police raid on an alleged Isis cell near the Syrian border. A mobile phone was also seized.
A source told the Herald Sun police believe he was planning to "bomb the service or drive a car into the crowd".
Police evacuated the Gallipoli site and were conducting a thorough search to check for bombs in the area just hours before the dawn service was due to begin.
Turkish nationals were banned from attending the dawn service, which Australia's Chief of the Defence Force Angus Campbell is due to be at, amid heightened security fears.
The Department of Veterans' Affairs said the dawn service would go ahead.
"The Australian Department of Veterans' Affairs and the New Zealand Defence Force (joint lead agencies) are aware of Turkish media reports that the Turkish National Police has arrested an individual who is alleged to be involved in activities designed to disrupt Anzac services at Gallipoli," the department told News Corp.
"This is a matter for the Turkish Authorities.
"Australian and New Zealand agencies are liaising with the responsible Turkish authorities in relation to this media reporting."
It follows inflammatory comments made by Turkish President Recep Tayyip Erdogan after the Christchurch terror attack last month. President Erdogan said New Zealanders and Australians who travelled to Turkey with bad intentions would be returned in coffins like their ancestors at Gallipoli.
He also repeatedly used footage of the mosque massacre at a campaign rally.