Almost two dozen women from across the country have added their names to a sex discrimination and sexual harassment lawsuit against securities broker Smith Barney Inc., the largest class action case of its kind against a major Wall Street investment house.

In a complaint filed in California and in an amended complaint filed in New York City, both within the past two weeks, the 26 named female plaintiffs, who work or worked in Smith Barney offices across the country, allege they were systematically excluded from lucrative broker jobs amid a male-dominated fraternity house atmosphere in which women were harassed, intimidated, fondled and subjected to coarse and abusive language. They allege in the lawsuit that women were sidelined into low-paying jobs as sales assistants handling administrative and secretarial chores.

The women are bringing the lawsuit as a class action case because Smith Barney, along with other securities firms, requires employees to submit to binding arbitration in employment disputes. The women allege that has deprived them of their rights to a jury trial and impartial adjudication of their claims. Instead, they allege, they are compelled by terms of these employment agreements to submit individual cases to industry-chosen arbitrators who overwhelmingly are older, white men and longtime participants in the securities industry.

The Smith Barney case is unusual because it alleges discrimination by white-collar managers at a number of different branch offices of a prominent professional services firm, according to attorneys who handle sex discrimination and harassment cases.

Smith Barney spokesman Bob Connor said the allegations are "totally false," but declined to discuss them specifically. "These are allegations -- lurid allegations -- and they are nothing more than that," he said.

Smith Barney spokeswoman Mary McDermott said the company has a "very strong policy" against sex discrimination and sexual harassment, in which "every complaint is thoroughly investigated."

"We do not hesitate to take action when we think the behavior or action is not good," McDermott said, adding that employees have been extensively trained in sex discrimination and that some employees have been fined or otherwise punished for transgressions.

McDermott said the pursuit of class action litigation was a way to get around arbitration, which she called a "less expensive and less time-consuming way to resolve client or employee disputes."

The lawsuit names as codefendants the New York Stock Exchange and the National Association of Securities Dealers, which administer the arbitration in employment cases involving securities firms. Ray Pellecchia, a spokesman for the NYSE, declined to comment on the case or to discuss how cases are arbitrated before the NYSE, citing the pending litigation.

Reid Walker, a spokesman for the NASD, said it would not comment on the litigation "at this point."

But Ellen Vargyas, legal counsel for the U.S. Equal Employment Opportunity Commission, said the class action strategy may be the only way employees in the securities industry can seek effective resolution of their problems, because it may permit individual employees to escape from binding arbitration agreements. She said that courts have ruled against the plaintiffs in individual cases that have sought to circumvent the industry-sanctioned arbitration panels.

Vargyas said the EEOC has opposed the mandatory arbitration agreements imposed by the securities industry because they remove cases from the public courts into what she called a "purely private form of justice, and that is justice' in quotation marks."

Vargyas said such agreements "have very effectively bottled up securities disputes in the civil rights area."

The Smith Barney case is another in a growing list of high-profile cases challenging alleged sex discrimination and sexual harassment in U.S. workplaces. The EEOC has filed a class action sexual harassment case involving hundreds of women workers at a Mitsubishi Corp. auto plant in Normal, Ill., and class action litigation is pending against the American arm of the Swedish pharmaceuticals firm Astra AB, according to court documents filed by the EEOC in a related Astra matter. In addition, a case involving 21 women miners in Eveleth, Minn., who won their class action case, is reaching its conclusion after 12 years of litigation.

Plaintiff Pamela Martens, 50, who had more than 1,000 clients and managed a $187 million asset base at Smith Barney at the time she was fired in 1995, has taken the lead in the case. Martens and four other women who worked at the Garden City, N.J., branch office allege their boss addressed them by vulgar sexual terms for the female anatomy and encouraged male co-workers to do likewise, compelled women workers to wear short skirts to serve men at a charity event, and constructed a basement room called the "Boom Boom Room," from which women were excluded and where, men joked, women's sexual harassment complaints would be "dealt with."

"It's like they have a manual in their heads as to how to crush women," Martens said in a telephone interview, adding that she believes she was unjustly fired because she complained to top company officials about the way women were treated.

The lawsuit alleges that Smith Barney's discriminatory hiring pattern has led to a work force in which fewer than 5 percent of the company's 11,000 brokers are women, and in which only 13 of 440 branch offices are headed by women.

Smith Barney spokeswoman McDermott said that 12 percent of its brokers are women, which she said was "typical" in the securities industry, and that there are really 380 branch offices, with 10 of them headed by women.

The lawsuit was first filed in May, with three named plaintiffs. Since then, in the wake of television coverage and newspaper accounts of the suit, many other women have joined the case. The lawyers for the women say they have heard from as many as 100 women who are interesting in participating in the case. The named plaintiffs include present and former Smith Barney employees from around the country, including branch offices in 11 states, including such sites as Davenport, Iowa; Los Angeles; New York City; Southfield, Mich.; Richmond; and Tampa. CAPTION: Pamela Martens, who managed $187 million in assets at Smith Barney when she was fired in 1995, is now a lead plaintiff in case.