Philadelphia has finally taken a long overdue step to prove that it means business with its efforts to increase minority participation in lucrative government contracts.

For the first time, the city has sanctioned a company accused of sidestepping laws designed to provide a share of city work to companies owned by minorities, women, and the disabled.

Given the city's dismal record of leveling the field for minority-owned businesses, this shouldn't be the last time that the city punishes companies that try to make a mockery of its program.

An agreement reached last week with Ernest J. Bock & Sons Inc. bars that firm from getting any new city contracts before April 2012.

That may amount to a wrist slap to a company that has won $224 million in city contracts since 1996, but it's something.

At issue is a $35.9 million contract awarded in 2007 for construction to expand Philadelphia International Airport. City Controller Alan Butkovitz accused Bock of submitting a bid for work that included minority participation but not actually using those subcontractors on the project.

Bock took the voluntary suspension to avoid a lawsuit. The company also agreed to provide training to help minority contractors better compete for business.

Mayor Nutter has hailed the agreement as a turning point. True. But those critics who contend the city should have sent a stronger message with tougher sanctions against Bock are right.

Under city law, companies submitting bids of $250,000 or more are required to offer and implement plans that give a share of the work to companies owned by minorities, women, or the disabled. Too many bidders have found ways around the rules.

Nutter recently announced that through the first half of the current fiscal year, 24 percent ($83 million) of the contracts issued directly by city departments went to firms owned by minorities, women, or the disabled. That's near the city's goal of 25 percent.

The city's improvement is laudable, but unsatisfactory. In fact, in a town in which 55 percent of the population is nonwhite, the level of minority participation in city contracts is mystifying.

It is also disappointing that the problems with Bock's contract were documented by Butkovitz's office, and not by the city Office of Economic Opportunity, which is supposed to monitor contracts.

There's no question about Nutter's sincerity in wanting to give more city work to qualified minority contractors. But to do that, he must go after other companies paying only lip service to his goal.