Vic cop who 'punched' cuffed teen cleared

A police officer who allegedly punched a handcuffed teenager in the head at a pro-marijuana rally in Melbourne has been cleared of wrongdoing.

Footage of the incident shows the girl being arrested during the 420 rally in April last year at Flagstaff Gardens.

She reportedly spat in the face of a female officer, who then appears to deck the girl in footage seen by AAP as she was being led away.

The girl is understood to have been charged with trafficking drugs, possessing drugs and assaulting an officer.

Her matter was finalised at a children's court on November 1, Victoria Police said.

Victoria Police confirmed to AAP on Wednesday that Professional Standards Command had finished an investigation into the incident and "the officer involved was cleared of any wrongdoing".

Liberal Democratic Party MP David Limbrick, who spoke at the rally, first asked in parliament last June about the officer's actions.

He was told this year that the police officer's action were not disproportionate.

"The conduct of the officer in question was investigated by Professional Standards Command, with the determination made that the action of the officer was not disproportionate in response to the protestor's actions," Police Minister Lisa Neville said in a reply to him.

"The matter has been finalised."

Mr Limbrick questioned on Tuesday how it was "proportionate".

"This surely fails the pub test, let alone any standard of professional policing," Mr Limbrick said in a statement on Tuesday.

"If the police minister is willing to accept this standard in the police force, now it is up to the premier. "