Chicago officials, still embarrassed by the violent clashes between police and demonstrators that marred the 1968 Democratic National Convention, yesterday urged Democrats to return to their city in 1984.

"We would like to hold the convention again and erase some of the residual bitterness that unfortunately exists from the 1968 convention," Illinois state Sen. Phil Rock told members of the Democratic Party's site selection committee.

The 27-member committee is meeting here for two days to review the bids of Chicago and four other cities seeking to stage the 1984 convention, an event estimated to pump $30 million into the economy of the host city.

New York City, host of the past two Democratic conventions, also made a presentation yesterday. Washington, Detroit and San Francisco are in the running as well.

Chicago Police Superintendent Richard Brzeczek, who addressed the panel, said his 14,000-member force is made up of a "new breed" of police officers who are more concerned with "crowd management" than "crowd control" and wouldn't repeat the mistakes police made in 1968.

"Fifteen years is a long time," Brzeczek said. "We are a new department. We are a young department."

Mayor Edward I. Koch, who headed a delegation of New York City officials and business executives, told the committee that it would minimize the risk of mishaps or shortages of hotel rooms and facilities by returning to New York. "If you come in 1984, we're going to give you the grandest time of your lives and we'll elect the next president," Koch said.

Some observers say they believe that San Francisco has the edge, primarily because Charles T. Manatt, chairman of the Democratic National Committee, is a Californian.

Also, Washington's convention bid is thought to be in trouble because city officials have not guaranteed a minimum of 20,000 seats for convention-goers.