NEW YORK — Mayor Bloomberg, in a startling departure from his pro-immigration stance, is testing a new program designed to chase down sponsors of legal immigrants who end up on certain kinds of public assistance, and the city intends to make the sponsors pay back money to the government.

The threat is being made by the city’s Human Resources Administration, which is circulating a press release warning that it will start sending out in August letters to sponsors of immigrants who are not citizens but who are receiving cash assistance from a program called Safety Net. It estimates that there are 12,000 sponsors the city could go after, but says it expects that it will only recover from about 8% of them, or 960 cases. 

Mr. Bloomberg’s demarche, which was signaled in the budget earlier this year, has been little-remarked-upon. In the large scheme of things it is a modest test. Yet it contrasts sharply with the mayor’s generally welcoming stance toward immigrants. In 2007, the mayor denounced Governor Romney of Massachusetts for saying that the federal government should slash funding for cities that don’t strictly enforce immigration laws. “Boy, let them come,” Mr. Bloomberg said at the time in a riposte to Mr. Romney, who’d denounced New York as a “sanctuary city” for illegal immigrants.

Describing New York City’s new policy last week, the Bloomberg administration insisted that the city “believes that immigrants coming here from countries throughout the world are vital to the success and vibrancy of our City. We also believe in personal responsibility.” It called its initiative “only one small component of HRA’s ongoing recoupment and recovery efforts that we conduct as part of our regular business. Additionally, we are ensuring the commitment by the sponsor is honored.” 

The city said its policy “will not affect the most vulnerable including those who are victims of domestic violence, refugees, or those who are seeking asylum.” It said the program will not affect food stamp benefits of non-citizens or their public health insurance. It said it is acting because of a federal law that requires sponsors of non-citizens to repay local service districts for cash assistance benefits “obtained by the sponsored non-citizen as far back as 10 years.” But it said HRS “will collect for the past five years.”

The Bloomberg administration insists it will target only relatively prosperous sponsors. “HRA will collect the amount of the cash assistance benefit from the sponsors who have enough income and/or assets to do so,” it said. “The money does not come from the non-citizen receiving Safety Net. If the sponsor is on public assistance themselves or on a low fixed income, we will not seek recovery from them. Sponsors who earn a higher salary, own property and/or earning income from it, should and can honor their commitment.”

New York’s pending actions against sponsors of immigrants echoes, if only indirectly, initiatives by other jurisdictions to collect from citizens for various services. The Drudge Report was headlining a CBS report on a bid by Passaic, New Jersey, to charge as much as $1,000 for certain kinds of calls to the fire department and as much as $600 for car fires. Those initiatives appear to be aimed at insurance companies. Other efforts by Passaic involve fees for designated handicapped parking.