A gunman who tried to rob a southern Sydney pub ended up in hospital after staff overpowered him early on Sunday.

Police said staff at the Engadine Tavern wrestled a gun from from the man's hand as he allegedly tried to steal money from a safe behind the bar about 1.15am.

Miranda police duty officer Inspector Mick Merrett said the alleged offender smashed through a glass door as the pub was closing, threatened to harm a male employee with a gun and yelled at patrons to lie on the floor. But the only thing the would-be-thief took away from the robbery were several bumps and bruises.

''The offender was disarmed and overpowered by a number of staff and in the course of that struggle the offender suffered a number of injuries whilst he was being subdued,'' Inspector Merrett said.

A patron called triple-0 during the attempted robbery and police arrived at the Station Street pub a short time later.

Police arrested a 27-year-old Kirrawee man and paramedics took him and a staff member to Sutherland Hospital to treat them for minor injuries.

Detectives are investigating possible links with an attempted robbery at Heathcote earlier in the night and several other armed robberies in recent weeks.

The man was refused bail and was expected to appear before Parramatta Bail Court on Sunday.