Train jumper a 'bloody idiot' says WA premier

A man filmed train surfing then taking a death-defying leap from a bridge into the water below is a "complete, utter, bloody idiot", West Australian Premier Mark McGowan says.

In the footage posted on social media, the man waves to the camera then jumps off the train on the Fremantle Railway Bridge, landing in the Swan River just metres from a concrete pylon.

"That guy is a complete, utter, bloody idiot," Mr McGowan told reporters today.

"He endangered his own life (and) he set a very poor example for others."

Public Transport Authority spokeswoman Claire Krol said the agency was also "incredibly disappointed" by the incident.

She said the train was travelling at about 45km/h and the man obviously did not consider the fact he would not drop straight down.

He was also very close to 25,000 volt wires that could have electrocuted him, Ms Krol said.

The PTA is reviewing CCTV footage and police are also investigating.

It is possible the man could be charged with trespassing, which carries a maximum penalty of one year in prison and a $12,000 fine.

"We are investigating what can be done and whether or not the penalties are sufficient," Mr McGowan said.

There are already measures in place to prevent people climbing onto trains, but Mr McGowan says it is difficult to stop people doing "completely, utterly ridiculous things".

WA Opposition Leader Mike Nahan said a crackdown was necessary, describing it as a "really dumb, deadly, dangerous thing to do".

"Young boys do stupid things and that is really stupid, endangering not only their life but the life of rescuers, and will lead to copycats," he told reporters.

A man was last year fined $1000 for train surfing between Leederville and Glendalough stations.