An armed gang have been thwarted in their attempts to rob a bowling club in Sydney's west - unaware that a group of motorcyclists had rented a room inside.

Three men stormed into the Regents Park bowling club around 8:50pm last night interrupting around 20 people playing trivia.

They were carrying machetes and knives - ordering everybody onto the ground and approaching staff at the bar.

But what they didn't know was that a motorcycle group, the Southern Cross Cruisers were holding a meeting in the auditorium - the group heard what was going on and confronted the men – around 50 people began running at the robbers with chairs.

Witness John says the robbers got the shock of their lives.

“In the auditorium a biker group were having their annual meeting of about 80 of them. All of a sudden 50 guys with chairs and that came out of the bikers group, throwing chairs at them…”

The robbers tried to flee - one was stopped by a biker in the car park the other arrested in nearby Regent Street.

One man is in hospital after running through a glass door in his panic to get away. CCTV vision has captured the incredible moment where he crashes thorugh.

Police are still looking for a third offender.