Victoria Police has issued its members new strict guidelines on appearance.

An email sent to staff by Chief Commissioner Ken Lay says men must have short tidy hair, with no extreme colours.

They are allowed neat moustaches but no beards or other facial hair, with the exception of practising Sikhs.

Female officers with long hair must have it tied back, with no ponytails allowed.

The Police Association's Senior Sergeant Greg Davies has welcomed the changes, which will be introduced next month.

"I think it's clear policing is becoming more and more of a profession than a past time and a professional outlook and appearance is an important part of it all," he said.

"Police need to gain back some respect that has been lost over the past decade or so and this is a good step towards achieving that."