Black was wanted on a revocation of parole warrant over his alleged involvement in a shooting incident at Dapto last November when he allegedly armed himself with a knife and joined Leal in robbing the Winnima Way business on Tuesday afternoon.

It is alleged Leal was armed with a handgun, while Hasiuk stayed inside the car during the robbery and acted as the getaway driver.

The trio made off with $1000 from the till, police will allege.

Meanwhile, officers allegedly traced the vehicle involved in the incident to a house in nearby Warwick Street about three hours later.

Read more: Berkeley post office manager speaks out after gunpoint robbery

All three men were arrested at the scene. Leal was apprehended within about 30 minutes after police arrived, however Hasiuk and Black refused to give themselves up and were involved in a three-hour stand-off with police.

They eventually surrendered about 10.45pm.

Neither Leal or Black applied for bail in Wollongong Local Court on Wednesday and both will remain behind bars until at least April.

However, Hasiuk sought release from custody, with defence lawyer Cate Doosey saying the case against the 32-year-old was a weak one.

"Police are relying on coincidence of time of the robbery and the time of [the car] arriving at the home," she said, adding there was no evidence currently available that linked Hasiuk to the robbery.

"There's a dearth of information before the court. It's a relatively weak circumstantial case."

Magistrate Susan McGowan disagreed with Ms Doosey's assessment of the strength of the case against Hasiuk and refused to release him on bail.

In documents tendered to the court, police said the post office's manager, Samir Parekh, was working behind the counter when an Audi pulled up outside and two men with balaclavas on their faces got out and entered the store.

It is alleged the man armed with a knife approached the counter and demanded money before grabbing about $1,000 from the till, while the man wielding the gun kept it trained on Mr Parekh.

However, Mr Parekh managed to press the silent duress alarm before locking himself in a rear room and the two men fled to the waiting vehicle, which police will allege was then driven to the Warwick Street address.

All three cases were adjourned for further mention in April.