A 24-year-old Sydney man arrested on terrorism charges is understood to be linked to alleged plots targeting government buildings.

The Bankstown man, Farhad Said, has been charged with one count of conspiracy to conduct an act in preparation for a terrorist act.

He was arrested by counter-terrorism police outside his home on Thursday morning, as part of Australia's biggest counter-terrorism investigation.

It is alleged Said is connected with a number of men already facing charges of possessing documents designed to facilitate a terrorist act.

Federal investigators have previously alleged the group was planning to target government buildings such as the headquarters of the Australian Federal Police and the Garden Island Naval Base in Sydney.

Said's case has been briefly mentioned in a Sydney Court, where he did not appear.

His lawyer Muhammed Tehseldar told the magistrate: "I'm not in a position to apply for bail."

The arrest by the Joint Counter Terrorism team is part of the ongoing Operation Appleby investigation.

Police are reassuring the public that there is no new threat to the community.

The Joint Counter Terrorism team have charged 14 people in relation to Operation Appleby since September 2014.

Said's case will return to court on June 8.