NEW ORLEANS (AP) _ The clubs that stage the gaudy parades and opulent balls leading up to Mardi Gras range from rowdy to blue blood, all white to mostly black, all male to women only.

Their distinctive membership rolls have now run up against City Hall.

The City Council last week prohibited the 64 krewes that organize parades and parties during Carnival, the two weeks of celebrations leading up to Mardi Gras, from discriminating against prospective members on the basis of race, sex, age, disability, religion, ethnic background or sexual orientation.

''There may be some day a generation that will enjoy Carnival feeling they can participate in any and every aspect of the festivities,'' said Councilwoman Dorothy Mae Taylor.

An ordinance approved Thursday gives the city the right to withhold parade permits after the 1993 Carnival season from any club found to discriminate. Violations carry a maximum penalty of five months in jail and a $300 fine.

A compromise delays enforcement of the penalties for a year and gives the krewes until November 1992 to work with city officials to resolve problems with the ordinance.

Nobody expects immediate differences, even after that, said Bill Quigley, a civil rights lawyer and Ms. Taylor's consultant on the law.

''These groups didn't become what they are overnight and I don't think anyone expects them to change into multiracial, multiethnic organizations overnight,'' Quigley said. ''The ordinance mandates equality in opportunity, not necessarily equality in result.''

The krewes, which organize events such as the all-black Zulu Parade and the all-female Iris Parade, have been racially and sexually segregated during 150 years of Mardi Gras celebrations.

Each sponsors a parade during Carnival and hosts formal parties with exclusive guest lists.

Many krewe captains said their major objection to the ordinance is the requirement that membership not be limited on a basis of sex. Some groups are integrated racially, but most are exclusively male or female organizations.

''We don't have any stipulations preventing anyone from becoming a member,'' said Irma Strode, 84, the captain of Iris for 30 years. ''We've never had a man ask to join. Why would they? They have their own organizations.

''We started as a group of friends and that's what we still are,'' she said. ''Friends sponsor their friends and as openings arise, we admit them. We have a waiting list of people who want to join, but we only allow 500 members. That's all we have room for on our floats and at the ball.''

Forcing krewes to accept members of the opposite sex would destroy their distinctive nature, said Beau Bassich, a former king of Carnival.

''It could kill Mardi Gras,'' he said. The ordinance would ''change Carnival into something different that is regulated by government and much less interesting.''

The organizations are traditionally shrouded in what Bassich called ''tongue-in-cheek secrecy.'' Membership is not made public. Members appear masked at Carnival.

For most of the krewes, membership is limited by the financial ability to pay club dues, which may run more than $1,000, and for costumes and ''throws,'' the beads and novelties riders toss from parade floats. Annually, membership may cost more than $2,500 when everything is added up.

But money alone is not enough to get someone into the old-line clubs, those sanctuaries of the cream of the city's aristocracy.

The krewes in the Mardi Gras Coordinating Committee opposed the ordinance because they had not had enough time to study it, Bassich said. ''This is not a statement that we are opposing this on a civil rights basis,'' he said.

Quigley said the law won't require affirmative action and groups that prove their rosters are full by their usual standard won't have to add new members just to include minority applicants.

''The question is whether or not they discriminate, not whether they actively recruit a cross-section of the community,'' he said. ''This ordinance is about opportunity, not about quotas.''