The arrest of a policeman who is expected to be charged for a brutal attack on a woman has undermined Chief Commissioner Ken Lay's public campaign against domestic violence.

The senior constable from Belgrave allegedly punched the woman, believed to be his partner, after wedding celebrations in Victoria's high country turned ugly. The policeman was only suspended on Friday, a day after Victoria Police was contacted by Fairfax Media.

Victoria Police Chief Commissioner Ken Lay's public campaign against domestic violence is being undermined by charges being laid against some of his officers.

The couple had returned to a Mansfield motel in the early hours of Sunday morning following a wedding at the base of Mount Buller.

Security footage captured the couple with up to eight other intoxicated wedding guests, "crowded around" in the Alzburg Resort carpark at 2am, a resort employee said.