A new internal investigation has been launched into three West Australian police officers who were filmed punching and kicking two people they were arresting.

The video of the December 2016 arrest in Hamilton Hill, in Perth, was played in court last month as the arrested pair faced charges of assaulting police, obstruction, and providing false particulars.

It showed the officers kicking the woman and punching the man up to 20 times.

The man involved was fined $100 for obstructing police, but the other charges were thrown out.

The magistrate criticised testimony given by the three constables during the court session on October 10.

Following a review of the video and court transcripts the Internal Affairs Unit has launched a renewed investigation into the conduct of the three officers.

They have been stood aside and restricted to non-operational duties pending the outcome of the probe.