An “incredibly dangerous” stunt has been filmed on top of one of Perth's newest and biggest landmarks.

Video shows someone on top of Matagarup Bridge in East Perth, filming towards Optus Stadium then back towards the city.

At one stage you can see a foot dangled over a gap in the railings, with the person behind the camera standing about 70 metres above the footbridge.

Camera Icon An “incredibly dangerous” stunt has been filmed on top of one of Perth's newest and biggest landmarks. Credit: Matt Jelonek

Main Roads labelled the stunt “incredibly dangerous” and police are now investigating.

Police say it could be a trespassing offence, but they have to work out who the person in the video is.

This video was posted online today and it's not clear when exactly it was filmed.