The increasingly visible homeless population in New York City is a "mix" of perception and reality, Mayor Bill de Blasio said in a radio interview Tuesday.

"Yes, there is something real going on here. It is much more an economic problem that it's being acknowledged to be," he said. "There are quality-of-life problems with some homeless folks and that will be addressed very forcefully. . . . And there's also a lot of homeless folks who don't do anything wrong or anything illegal."

De Blasio added that the issue was in part the result of "mistakes of government policy," noting the end of the Advantage rent subsidy program in 2011 during Mayor Michael Bloomberg's administration.

The Democratic mayor was a guest on WNYC's "The Brian Lehrer Show" to take on-air listener's questions for the second time in two weeks. He appears to be making a more concerted effort to directly communicate with New Yorkers, on Monday launching a surprise Twitter chat to answer the public's questions with #BDBchat.

But unlike his predecessors, including Bloomberg, de Blasio has not hosted a town hall forum or his own call-in radio show.

His focus Tuesday on WNYC was homelessness. His office announced late Monday that his deputy mayor in charge of health and human services, Lilliam Barrios-Paoli, was leaving to chair the city's Health and Hospitals Corporation board. Barrios-Paoli, the highest-ranking official to depart the administration since de Blasio took office in January 2014, oversaw homelessness issues.

The mayor said Tuesday that her departure was her "personal decision" and commended her for "stemming the tide" of homelessness.

The city's shelter population was nearly 59,000 in June 2015, compared to 42,000 in December 2011, according to the Coalition for the Homeless.

"There's no inconsistency between saying that these are human beings who, in many cases, need our help either for economic reasons or mental health or substance abuse reasons -- and we will provide that help to the very best of our ability," de Blasio told Lehrer. "But at the same time, we're not going to tolerate disorder. We're not going to tolerate homeless encampments."

A caller who identified herself as Margo in Manhattan, 67, a homeless woman living in a convent, asked for a meeting with de Blasio and he obliged.

When Lehrer played a clip of former Mayor Rudy Giuliani telling NBC New York last month that homeless people should be "chased out of the city" and he had done so when he was chief executive with the help of NYPD Commissioner William Bratton, de Blasio alluded to comments by Cardinal Dolan and Pope Francis: "We don't chase human beings who are in crisis, we try and address their problems and get them to the kind of help they need and off the streets."