ATLANTIC CITY, N.J. (AP) _ Neighboring casino hotels expect to take up the slack Saturday when Caesars Atlantic City closes its casino for a day under a state penalty for helping a compulsive gambler lose millions embezzled from his employer.

It was the harshest penalty ever imposed in this city's 71/2 years of casino gambling, and the first time a casino has been ordered temporarily closed in the United States for violations of state regulations.

But Caesars officials reminded patrons that its hotel, restaurant and showroom would remain open Saturday, one of the busiest weekends of the year here.

And while industry officials predict a revenue loss of between $700,000 and $800,000 because of the shutdown, they doubt that it will have an effect on Caesars' good fortune.

The closing from 10 a.m. Saturday to 6 a.m. Sunday comes as Caesars leads the 11 casinos in this resort in market share, a gaming anaylst said.

''I view the impact as negative only in the very short term,'' said Steven Eisenberg, an analyst with Bear, Stearns & Co.

Caesars Senior Vice President Alfred Cade said earlier this week the company expected its hotel would be 95 percent booked Saturday and that a one- night performance by singer Alan Tam was sold out.

Casino employees will be paid their wages and reimbursed for lost tips, officials said. Caesars planned seminars for employees to review state gaming regulations and invited a leading national expert on compulsive gambling, Dr. Robert Custer, to spend several hours with 30 top executives, Cade said.

''So the place is going to be very, very busy on Saturday,'' Cade said.

Alan Rosenzweig, a spokesman for Bally's Park Place, said that casino hotel planned no special efforts to lure in gamblers from Caesars.

''We assume that when people come out (of Caesars) looking for a casino, they will have two ways to turn,'' he said. And on one side is Bally's.

The state sanctions, including fines totaling $36,500 against Caesars employees, stemmed from the casino's violations of credit regulations and cash procedures in its dealing with Brian Molony, an assistant manager at the Canadian Imperial Bank of Commerce in Toronto.

Molony, a compulsive gambler who bet as much as $75,000 on one hand of baccarat or one roll of the dice, deposited $9.9 million at Caesars during a 15-month period.

He pleaded guilty in November 1983 in Toronto to charges that he embezzled $10.2 milion from his employer and was sentenced to six years in prison.

''He would arrive at the casino with his gym bag filled with cash and deposit it with casino representatives,'' Arnie Wexler, president of the Council on Compulsive Gambling of New Jersey, said of Molony.

''He ate cold chicken sandwiches right at the gambling table so he wouldn't have to spend time away from the table,'' he added.

Wexler said the one-day closing was not a harsh enough penalty. He said Caesars should have been fined and the money used to help compulsive gamblers.

But gaming officials have said they think the shutdown sent a message to gaming hall operators that New Jersey regulators will not tolerate wrongdoing.

Caesars held the previous New Jersey record for the highest penalty, paying $257,000 in 1983 for violations of internal auditing procedures and for interfering with state inspectors as they monitored the wagering of an Italian national.

The record fine in Nevada is $3 million imposed in 1984 against the Trans- Sterling Corp., owner of the Stardust and Fremont casino hotels, for allowing a skimming operation, in which money is removed before taxes are paid. The owner's license was also revoked.