It’s the first boost in federal housing subsidies in four years, but it comes with one big catch.

Thursday night, the U.S. House of Representatives appropriations subcommittee approved $100 million for new housing vouchers. The money would be slated for people on Section 8 waiting lists who are also in welfare-to-work programs.

But on Friday, low-income housing advocates tempered their celebration with predictions that the new funding would likely be linked to a much-loathed GOP overhaul of the nation’s public housing system. Progressive lobbyists have fought against the measure, sponsored by Long Island Republican Rick Lazio, which would open up a greater number of public housing units to working-class people–and deny housing to many of the nation’s poorest applicants.

“It’s a disgusting scenario [that he would] use that leverage,” said Linda Couch of the National Low Income Housing Coalition, which has opposed Lazio’s efforts for two years. The appropriations bill, Couch said, must be passed to keep all federal housing funds flowing–making Lazio’s bill much more likely to be passed than if Congress considered it on its own merits.

Lazio’s bill could be piggy-backed onto the voucher increase as soon as next week, when the House Appropriations Committee meets.

The appropriations package approved by the Senate last week was more modest, more specific–and it didn’t have the that house’s version of public housing reform in it. It labeled the welfare-to-work housing vouchers a “demonstration program,” approving only $40 million to be split equally between eight cities nationwide, including Kansas City, Anchorage and New York. Advocates estimate that the bill would fund between 7,000 and 8,000 new vouchers. To put that in perspective: A study released Monday by the Center on Budget and Policy showed that the number of people seeking cheap apartments grew from 3.8 million in 1993 to 4.4 million by 1995.