Opponents of legislation designed to give college tuition breaks to illegal immigrants in Maryland say they are on track to collect the thousands of signatures needed to try to overturn the measure that passed the General Assembly last month.

Del. Neil C. Parrott (R-Washington) and Del. Pat McDonough (R-Baltimore County) are leading the effort to give voters a say in whether to uphold the bill.

Parrott said volunteers in most of Maryland’s counties are gathering signatures and spreading the word at grocery stores and community events that “our tax dollars are going to fund illegal aliens,” he said. “Now is not the time to be spending money on what is an unlawful program.”

Sen. Victor Ramirez, the Prince George’s Democrat who sponsored the legislation, said immigrant advocates and other proponents of the measure would mobilize to educate voters and ensure that the signatures gathered are valid. He called Parrott’s message “misleading” and said the legislation would not give immigrant students a free ride.

“It gives kids the opportunity to go to college and be treated like all other Maryland high school graduates,” Ramirez said.

Gov. Martin O’Malley (D) has said he would sign the bill that would allow illegal immigrants who have graduated from Maryland high schools to pay in-state tuition at the state’s colleges and universities.

Students would have to provide proof that their parents or guardians are taxpayers, and would have to begin their courses at a community college. Those who earn an associate’s degree could transfer to a four-year institution at the lower in-state tuition rate.

Maryland would join at least 10 states that provide similar benefits to undocumented immigrants. But other states have moved in the opposite direction, including Virginia, where some lawmakers have tried to block illegal immigrants from enrolling in state colleges.

Putting a referendum on the ballot in Maryland is a difficult task. While many groups have tried in recent years, the last statewide measure to qualify was in 1991, according to the State Board of Elections. Voters in that election upheld less-restrictive abortion laws.

Opponents of the in-state tuition bill have until May 31 to turn in one-third of the required 55,700 signatures, or about 18,600 names. The final batch must be turned in by June 30.

Parrott said the group — Mdpetitions.org — has been encouraged by public support for its effort and hopes to turn in more than 36,000 signatures by the first deadline to ensure that the names can withstand anticipated legal challenges from supporters of the bill.