Lt. Gov. Pat Quinn and the Illinois News Broadcasters Association protested the policy in letters to state police Director Larry Trent.
They say it will discourage whistleblowers who believe telling the media is the only way to expose wrongdoing.
Police spokesman Lincoln Hampton says employees already were prohibited from talking to the media and the policy is meant to prevent confidential information from becoming public.
He says the policy change already was in the works before WLS-TV in Chicago reported last month on alleged misconduct by state troopers who act as bodyguards for Gov. Rod Blagojevich.