NY- It was a “slap in the face” for the cop accused of firing 31 shots at Sean Bell to party at an East Side hot spot just a day after he was indicted in the fatal shooting, Bell’s pastor said yesterday.

Detective Michael Oliver shocked even his supporters when he dined on $180 pasta with truffles and $575 bottles of wine at celebrity hangout Nello’s on Saturday night – racking up a $4,200 bill.

“Him going out and celebrating and having a party, [he’s saying], ‘Hey, there’s nothing to this,’ ” said the Rev. Lester Williams of Community Baptist Church of Christ in Jamaica, Queens, where Bell was supposed to get married.

“It’s a slap in the face to us,” Williams said.

Oliver, 35, will be arraigned today on manslaughter charges along with Detective Gescard Isnora, 28, in the killing of Bell outside a Queens strip club on Nov. 25.

Detective Marc Cooper, 39, faces reckless endangerment charges.

Relatives of the victims blasted Oliver for going out for a night on the town with a friend from Spain and two beauties so soon after a grand jury charged him on Friday.

“I don’t really know what he was celebrating,” said Denise Ford, whose son Trent Benefield, 23, was shot and wounded alongside Bell, 23, and a third friend, Joseph Guzman, 31.

“There’s a young man under the ground,” said Les Paultre, whose daughter Nicole would have married Bell. “I’d think you’d like to show some kind of respect.”

Police insiders say Oliver showed incredibly bad judgment by indulging in $65 Dover sole at a high-profile restaurant.

“He just got himself convicted,” said one police union official. “We have to rein him in before he gets the other guys convicted, too. It’s all about perception.”

“His lawyer will sit him down and talk to him,” added another police source. “I guarantee this won’t happen again.”

The party-boy image may not directly affect the cops’ case, but public perception can sway high-profile jury trials.

Even supporters of the accused cops say the three have been warned to avoid appearing to thumb their noses at the victim and the black community.

Some of the accused cops asked whether they could attend the St. Patrick’s Day Parade – and were told to stay out of the public eye, sources said. “This has come up before,” a .police union insider said. “He and the others have been told to lay low.”

The Rev. Al Sharpton said Oliver’s taste for fine wine raises a .legitimate question about whether cops were drinking the night of the Bell shooting.

“The most striking thing is the amount of alcohol,” said Sharpton, pointing to reports of the dinner that had four people downing five bottles of wine. “How much alcohol was consumed on the night Sean Bell was killed?”

But detectives union chief Michael Palladino hit back at Sharpton, saying he has a “warped mind.” Oliver was not inside the strip club and has not been accused of drinking that night, Palladino said.

He also suggested that Mayor Bloomberg’s comments after the shooting that the 50 shots “sounds like excessive force” could provide legal grounds to move the trial out of the area.

“We will examine all of our options, including a change of venue,” he told WABC/Channel 7.

Palladino also took a subtle shot at Bell and two buddies, who faced off with cops as they came out of the Kalua Cabaret in Jamaica, a notorious strip joint. “There is a distinct difference between going to dinner with friends and partying in a dump called the club Kalua, which is overrun with drugs, guns and prostitution,” Palladino told the Daily News.