"Gov. Christie is personally holding this law back," said Chris Goldstein, executive director of the Coalition for Medical Marijuana for New Jersey.
The state Health Department, which is overseeing the medical marijuana program, did not elaborate Friday on Christie's statement.
"We are continuing our work on the program but are waiting for clarification on the application of federal law," Health Department spokeswoman Donna Leusner wrote via e-mail.
Supporters of legalizing the drug already had planned a rally Friday at the Statehouse to protest the 40th anniversary of President Richard M. Nixon's declaration of a war against drugs.
But Goldstein said there was more to protest after Christie's comments Thursday evening on New Jersey Network's On the Line program.
Christie, a Republican and a former federal prosecutor, said he was concerned that regulators might be prosecuted for following his directions if the medical marijuana program is started.
Only a half-dozen activists showed up at the rally.
In one of his last acts before leaving office in January 2010, Christie's predecessor, Democrat Jon S. Corzine, signed a bill to establish a medical marijuana program in New Jersey.
Advocates for the law say that Christie, who says he supports the concept but dislikes some of the details, has delayed implementation.
Regulations for the program have been drafted but are not yet finalized. Advocates don't like the proposals either, in part because they would limit the potency of pot available to patients. Lawmakers also have considered trying to invalidate the regulations, saying they fall short of the law's intent.
Six alternative treatment centers and nonprofit groups have been licensed to grow and sell pot to patients with conditions, including terminal cancer, multiple sclerosis and glaucoma.
Advocates say about 250,000 people in New Jersey have the conditions that could qualify them for medical marijuana recommendations.
But without regulations in place, it's looking less likely that the state will have legal marijuana sales sometime this summer, as Christie's administration previously said it would.
Roseanne Scotti, director of the Drug Policy Alliance New Jersey, said the state should move ahead because of how medical marijuana works elsewhere. Fifteen states and the District of Columbia allow medical marijuana.
"No state worker has ever been prosecuted. No state worker has ever been threatened with prosecution," Scotti said. "They would never prosecute state workers because honestly, it would be terrible PR for the federal government."
