Landlords who keep rent-stabilized units vacant could be forced to pay fees under a new bill introduced by a Manhattan lawmaker.

State Assembly member Linda Rosenthal is pushing a law that would force landlords to pay a fee if they intentionally leave rent-stabilized apartments empty, Crain’s New York Business reports.

Under the rules, owners would have to pay a penalty of the last legal rent after a unit has been vacant for three months. They would then face a fee each month that works out to be 150% of the last legal rent. The money will be funneled into a fund set up by Homes and Community Renewal that will support homeless people. Landlords would be able to avoid the fee if they can show they are doing renovations on the units, and they aren’t able to rent them.

The issue of keeping rent-stabilized units vacant is linked to the new rent reform legislation, which was introduced last summer and restricts the ways landlords can move previously stabilized apartments into the free market. Their ability to pass on the cost of renovations through rent hikes was also curtailed.

Real estate players have warned that some landlords will consider it more economical to keep units empty, rather than rent them out at a stabilized rate, and that the rules on renovation will lead to homes falling into disrepair.

“I’ve spoken to different New Yorkers who say they know there are empty apartments in buildings they’re trying to rent in, but they are not open to new residents,” Rosenthal told Crain’s. “Basically, landlords are warehousing apartments.”

Blackstone said in July it would pull back on apartment upgrades at Stuyvesant Town and Peter Cooper Village. A month later, The Real Deal reported the private equity giant was keeping stabilized units at the 11,000-apartment complex off the market, though Blackstone later said it would rent all the units out.

“The bill is unconstitutional, poorly written, and fails to address any of the severe housing problems New York State currently faces,” landlord group the Community Housing Improvement Program said in a statement this week. “New York State has serious housing problems. We need state lawmakers who are serious about finding solutions. Assemblywoman Rosenthal’s war on private property is political pandering at its worst.”

Rosenthal said that while the industry may hope the law will be altered, she has no plans to change tack.

“For years the scales were balanced in the landlords' favor,” she told Crain's. “These are very sensible rules.”