An anti-Islam extremist accused of plotting bomb attacks in Victoria appeared to boast that authorities had "no idea" of the danger he was planning, a court has heard.

Witnesses will also testify that Phillip Michael Galea, 32, talked about blowing up the headquarters of Melbourne's anarchists, the Melbourne Magistrates Court was told on Monday.

Galea is charged with collecting or making documents to prepare for terrorist acts between November 2015 and early August 2016.

He is also charged with doing acts in preparation for a terrorist act between September 2015 and early August this year.

Prosecutors are relying on evidence contained in secretly recorded phone conversations in which Galea talks to other people about his plans.

Defence lawyer Allan McMonnies said his client believes the conversations will exonerate him.

But Magistrate Charlie Rozencwajg cast some doubt, referring to some comments Galea allegedly made.

"If I say anything else, I'll get arrested," he allegedly said in one conversation, read by Mr Rozencwajg in court.

In another, Galea allegedly said: "They thought what I was planning before was dangerous. They've got no idea."

Police allege Galea researched homemade bombs, ballistic armour and guns.

He allegedly ordered ingredients for smoke bombs last year, and mercury - which has explosive properties - was found at his Braybrook home in November.

He also conducted surveillance of "left-wing" premises where he planned to launch deadly bombing attacks, police allege, and is accused of trying to recruit others to help carry out his plans.

Investigators say Galea has been linked to far-right groups Reclaim Australia, United Patriots Front, Patriots Defence League Australia, the True Blue Crew and also a "neo-Nazi, self-confessed militant group" called Combat 18.

Galea, who appeared in court via videolink, was remanded into custody to face a further committal mention on April 4.