TRENTON - In the wake of two fatalities at a rock concert at the PNC Bank Arts Center, New Jersey authorities are cracking down even harder to stop underage drinking at the entertainment venue.

Effective yesterday, alcohol is banned in the parking lot of the arena in Holmdel, in central Jersey. At Thursday night's Ozzfest concert, two men died and 83 people were arrested.

Police are investigating the deaths of the pair, identified as Raymond Guarino, 26, of Forked River and Patrick Norris, 24, of Coram, N.Y.

After possibly taking drugs and alcohol, both passed out in separate incidents at the concert, went into cardiac arrest and later died. State police said the men were believed to have ingested cocaine, marijuana and alcohol before their deaths, and troopers who searched Guarino's vehicle found small amounts of both drugs.

Although both of the fatalities were adults, 59 of the 83 who were arrested were charged with underage drinking. Other charges included distribution of drugs, lewd behavior and providing alcohol to a minor.

Authorities said the Ozzfest incidents were the latest in a long string of problems this season that led them to ban alcohol in the center's parking lot.

"This is a dramatic step to have to take, but one that is necessary given the potential consequences of such risky behavior," Gov. Jon S. Corzine said yesterday.

The first show to be affected was a concert last night featuring Velvet Revolver, Alice in Chains and Kill Hannah. Signs on the Garden State Parkway notified concertgoers of the alcohol ban.

Joe Orlando, a spokesman for the Turnpike Authority, which owns the arts center, said the ban affects all ages, so even those who can drink legally cannot bring alcohol onto the site; in the past, people over the legal drinking age have been allowed to bring alcohol to the center's parking lot and tailgate before and during concerts.

Depending on their age, violators face fines, expulsion from the premises and arrest.

Alcohol will still be sold inside the center, situated near the Shore.

Kevin Coyne, of Sewell, N.J., who attended Ozzfest, said yesterday that the all-day concert didn't seem particularly out of control to him, although he left about 5:30 p.m. and didn't spend much time in the parking lot.

"To me it was just a normal concert," he said. "I didn't see anything that was out of the ordinary." He added that the alcohol ban wouldn't keep him from attending future shows.

Coyne said many concertgoers seem to spend more time in the parking lot drinking than inside the venue watching the acts.

Orlando said police have arrested more than 200 at shows at the center in the past 10 days. *