The campaign by the anti-immigration Sweden Democrats pictured people sleeping on the street and apologized for "the mess". Critics regard the posters as racist disparagement of Roma migrants here.
"We're going to look at these texts and see if it crosses the line, according to the existing rules," David Löfgren, a rapporteur at the office of the Chancellor of Justice, tells Svenska Dagbladet newspaper.
As of lunchtime on Tuesday, the campaign had been reported 46 times to the Chancellor of Justice and 36 times to the Swedish Advertising Ombudsman, according to Svenska Dagbladet newspaper. News agency TT reports that SL, the Stockholm public transit service, had received nearly 2,000 complaints about the ads.
After a demonstration Tuesday evening, in which around 1,000 people were estimated to have taken part, people ripped down the posters in the subway station, according to police.