A security guard has told an inquest into the death of a man during a foiled robbery in Sydney's north, he feared for his life before the man was shot dead.

Nathan Brodbeck was shot in the chest by a security guard, Radion Primanzon, as he attempted to rob a cash-in-transit van outside Dee Why RSL in July 2010.

The 32-year-old had worked for the company that owned the van, Brinks, and was a former seaman with the Royal Australian Navy.

The inquest is examining whether the guard responsible should have drawn his weapon.

Raid Akkoushe was one of three guards at the scene, but did not fire the fatal shot.

The Counsel assisting the inquest has asked Mr Akkouche, whether he felt his partner was justified in firing the shots.

He has told the inquest he took cover when Brodbeck approached the van, and his partner was justified in drawing his gun.

Mr Akkouche said he was worried he would be shot, and Mr Primanzon was doing what he was trained to do.

Last year, a former policeman was jailed for providing the gun to Mr Brodbeck.