One of the city’s best known advocates for the homeless is stepping down.

Mary Brosnahan, the president and CEO of the Coalition for the Homeless, is leaving after three decades. Under her leadership, the group became the city’s premier defender of the homeless, and its budget grew from $1 million to $12 million.

In an exit interview with WNYC’s Jami Floyd, Brosnahan criticized Gov. Andrew Cuomo for moving too slowly with the creation of supportive housing.

“He said that he was going to build 20,000 units of housing support services, and we haven’t seen a single unit yet,” she said.

The governor said two years ago he'd create those units over 15 years and that the first units would become available in 2018. The governor’s office didn’t respond to a request for comment.

Brosnahan also said Mayor de Blasio’s goal of reducing the shelter population by 2,500 by 2021 is too modest. The administration says it needs to balance the needs of homeless families with those of low-income families who are on the waitlist for public housing. More than 60,000 people currently live in city shelters.