Hollywood personalities today denounced and boycotted a controversial congressional committee whose hearings here have been characterized as a "witch hunt" to identify users of cocaine and other drugs in the entertainment industry.

At the opening of two days of hearings by the House Select Committee on Narcotics Abuse and Control, committee members denied the "witch hunt" charges and heard testimony that among cities Los Angeles is a major consumer of drugs, with $300 million in illegal cocaine sales alone.

Many celebrities expected to testify Thursday have already declined.

Federal law enforcement officials dealing with drug trafficking here have said that the huge salaries of entertainment industry lawyers, producers, directors and performers have helped create a booming business for expensive and usually nonaddictive drugs such as cocaine.

"One Beverly Hills physician reported clients spending up to $300,000 per year on their cocaine habits," Los Angeles police narcotics division commander Robert J. Blanchard said in a statement to the committee. d

Grant Tinker, whose MTM company produces the television shows "Lou Grant," "The White Shadow" and "Hill Street Blues," said he decided against testifying becausw he concluded that the committee "could not help asking who snorts" cocaine and that he had no useful information about that.

"I am absolutely sure that cocaine use is no more of a problem here than it is on Capitol Hill," Tinker said.

In an interview, Tinker was critical of two recent articles in TV Guide magazine that suggested television and movie deals sometimes depended on the producer's ability to provide entertainment executives with cocaine.

They suggested that in order to sell a program I have to supply National Broadcasting Company President Fred Silverman with cocaine, and that's patently ridiculous," Tinker said.

Tinker added that television programs should provide antidrug information and said he had given Alan Horn, president of Tandem Productions, who is scheduled to testify Thursday, information on efforts to do that in MTM shows.

One of the most outspoken critics of the committee, "Lou Grant" star Edward Asner, has charged the panel with opening a vendetta similar to the anticommunist crusade in Hollywood in the early 1950s.

Asner charged that committee member Robert K. Dornan (R-Calif.) wants to punish movie industry supporters of his two-time Democratic opponent, Carey Peck, son of movie star Gregory Peck. Dorman denied the charge, and committee chairman Leo C. Zeferetti (D-N.Y.) said any suggestion the committee was engaged in some sort of witch hunt or inquisition . . . is simply not true."

Committee staff members said that despite the defections of many potential witnesses because of publicity about the hearings, they expected actors Dennis Weaver and Greg Morris to testify Thursday.

Actress Cathy Lee Crosby, who had initially welcomed an informal committee look at the drug situation here, said today that she had withdrawn because "media hype and sensationalism became more important than finding the solution to the problem."

Withesses ranging form Los Angeles Mayor Tom Bradley and California Attorney General George Deukmejian to police, Coast Guard and customs officials told the committee today that drug abuse affects all age, ethnic and income groups and may be involved in more than half of the crimes in the area.

Although he acknowledged that the most popular and profitable drugs are cocaine and marijuana, Drug Enforcement Administration regional director George Halpin said his investigators gave priority to halting sales of the addictive drug heroin because of the crime problem it causes as users steal to finance their habits.

Drug enforcement officials testified that they seize only about 10 percent of drugs entering the area. They traced the cocaine trail from growers in Peru and Bolivia to refiners in Columbia and then to Mexico for shipment by air or sea across the border.

Coast Guard Rear Adm. Alfred P. Manning said most of the freighters, fishing vessels and sailboats used in drug trafficking ". . . have extensive electronic equipment aboard of high quality and generally superior to Coast Guard equipment.

"We have no doubt that Coast Guard equipment.

"We have no doubt that Coast Guard vessel movemenmts . . . are carefully monitored, that our commuications are monitored for content and direction-finding and that smugglers are using aircraft to locate Coast Guard vessels at sea," he said.