Anti-terrorism raids in Sydney and Brisbane - ABC News (Australian Broadcasting Corporation)

A man has faced a Sydney court, charged with conspiracy to prepare for a terrorist attack on Australian soil.

Omarjan Azari, 22, was one of 15 people detained during a large counter-terrorism operation across Sydney this morning.

Commonwealth prosecutor Michael Allnutt told Sydney's Central Local Court the alleged offence was "...clearly designed to shock, horrify and terrify the community..."

It's believed the allegations involve a plot to behead a random member of the community in Sydney, on camera.

The court was told the charged stemmed from a single phone call intercepted a couple of days ago.

"It's been an immediate reaction to a clear, imperative danger," Mr Allnutt said.

"There is still an enormous amount of material for police to assess."

Azari did not apply for bail and the case was adjourned until November 13.