Local elected officials are looking for ways to crack down on illegally subdivided apartments in the Bronx and across the city after a recent fire at one such dwelling killed three members of a Belmont family.

One effort, a bill sponsored by Bronx Councilman Oliver Koppell, would require the Department of Buildings to seek a warrant to gain access to properties they suspect have been illegally converted if inspectors are turned away or unable to enter a building after two attempts.

Officials say city inspectors are often unable to gain entry to the properties.

Several complaints had been received about the site of the recent Belmont blaze, a foreclosed row house at 2321 Prospect Ave. that had been dangerously chopped up into several single rooms. Mayor Michael Bloomberg said building inspectors couldn’t get into the building to follow up on complaints.

Koppell said his legislation, if passed, would force city agencies to keep trying.

“I was shocked to find out this city practice,” Koppell said, about the practice of closing complaint cases after two failed attempts. “It seemed to me to be completely outrageous, and irrational. They’ve got to try to pursue it.”

Council Speaker Christine Quinn said the court system largely denies the city’s requests for access warrants, and that the Council will hold a hearing on the issue in June.

Koppell’s bill has lingered in the Council since it was introduced last October.

“I think this is prevalent citywide,” he said. “A lot of immigrants coming in are looking for inexpensive dwellings, and not being really aware of the law, they’re taken advantage of.”

The Belmont fire, which broke out in the early morning hours of April 25, killed 12-year-old Christian Garcia and his parents, Christina Garcia and Juan Lopez.