Sydney man Muhammad Abdul-Karim Musleh has pleaded guilty to helping foreign fighters enter Syria with the intention of engaging in armed combat.

Musleh was arrested by counter-terrorism police in 2016 some two-and-a-half years after allegedly helping three men travel to Syria.

Dressed in a black coat with slicked-back hair, Musleh stood in the dock at the NSW Supreme Court on Monday as his indictment was read out.

The court heard that in mid-2013 Musleh helped the men enter Syria "with intent to engage in a hostile activity in that foreign state, namely, engaging in armed hostilities".

He helped the men while in Sydney, Turkey and "elsewhere", the indictment states.

Musleh, who was due to go to trial later this year, softly replied "guilty" when asked to enter a plea.

He sat down, checked his watch and looked to his lone supporter in court as Justice Christine Adamson ordered the case to proceed to sentencing.

Musleh will remain on strict conditional bail and can return home with his wife and child until his sentencing hearing on November 6.