Sydney 's obnoxious seat-hogging commuter outed on Facebook

A man has been outed for his obnoxious behaviour on Sydney trains.

A fellow commuter posted on Facebook about inappropriate behaviour she claims she has encountered on the train network for some time.

"Totally packed train each Thursday morning, when I catch the Blacktown to Hornsby train. Every morning we are greeted by this person, when you ask him, to move his bag & feet you get the finger," the woman says.

"Please help this go viral maybe his parents will see just how polite he is not. Maybe the rail cops should travel on morning commutes as well. He commutes to Pymble Station.," she says.

"Maybe a 12 month ban as well as a hefty fine might teach him a lesson."

In Sydney, penalties for having your feet on seats on trains range between $100-$1100.

With over 16,000 people sharing the post and 8800 people liking it, the Facebook community was outraged.

"Spill hot coffee on him that way it'll look like he p*ssed himself when getting off the train. Just imagine how embarrassed he would when people would point & laugh him! Any takers ?! ..." was one comment.