By Steven Greenhouse

Ed Ott, the executive director of the New York City Central Labor Council, an umbrella group for the city’s labor unions, has an unexpected and unnerving warning for New York’s more than one million union members.

He warns that their wages and living standards will be threatened unless the city’s unions do far more to lift the incomes and living standards of the city’s nonunion working poor, including restaurant workers, supermarket cashiers and taxi drivers.

“Going forward, if we don’t raise the standards for the lowest-paid workers in the city, and there are literally hundreds of thousands of them, our own levels that we achieved — of wages, pensions and time off — they’re not sustainable,” said Mr. Ott, whose group is a federation of 400 union locals. “For a working class that is going to be making minimum wage or slightly above, what’s going to happen is that as taxpayers, that will create a social base for an attack on our own standards.”

Mr. Ott’s remarks, made in a recent speech at City University and in a follow-up interview, were an impassioned plea as well what he said was a “wake-up call” to the city’s labor movement. New York’s union movement has far more members than any other city’s, although it is widely viewed as less aggressive in unionizing and helping low-wage workers than the labor movements in Los Angeles and several other cities.

He said that many low-income workers who receive no paid vacation or sick days were bound to ask why many municipal workers are entitled to 40 days off per year — combining vacation days, personal days and sick days — in their first year on the job.

“There’s a danger that in the eyes of the majority of people we might be seen as too expensive,” said Mr. Ott, a former official with the Communications Workers of America and the Oil, Chemical and Atomic Workers Union who became leader of the labor council in 2006 after its previous president, Brian McLaughlin, was indicted on embezzlement charges. “If you have an extremely low-paid strata, you can’t believe they’ll say, ‘You should have another two sick days when I don’t have any.’ We have to find ways to elevate their status.”

Mr. Ott is glad that many union members — for instance, construction workers, telephone workers and teachers — have achieved middle-class status. But he voiced frustration that many unions showed little concern about lifting the status of low-wage nonunion workers. He made his remarks at a time when the number of nonunion workers has soared in traditionally union-dominated industries like construction and hotels.

Mr. Ott sees two working classes in New York: a unionized one that is doing well and a nonunion one that is struggling to get by.

“You see a working class on the subway at 6:30 in the morning and you see them at 8:30 at night heading home,” he said. “They work in the back of restaurants, they clean buildings nonunion, they’re child care workers, they’re in retail. Frankly, I marvel that these guys can find a way to live in this city. They work very hard. Most of these workers who work outside a union setting, they work more than one job or they work one job many hours.”

Mr. Ott said the union movement needed to work closely with less-well-off groups of workers — taxi drivers, domestic workers, restaurant workers, even freelance writers and computer workers — to help raise their living standards, not just for moral reasons but also for their own self-interest. “Every time you go to the bargaining table now, there’s downward pressure,” he said. “Even in the public sector, it’s ‘Any improvements you want, you have to pay for with concessions.’ That’s downward pressure, too.”

As part of his strategy, Mr. Ott took the unusual step of inviting the Taxi Workers Alliance, a group of several thousand nonunion immigrant taxi drivers, to join the Central Labor Council.

In his view, unions need to embrace immigrant workers and work closely with their advocacy groups. The labor council is working with Domestic Workers United to help enact legislation in Albany to improve wages and benefits for nannies and housekeepers. The labor council is also trying to make common cause with the Freelancers Union, a Brooklyn-based group that is seeking to provide affordable health and disability benefits to tens of thousands of freelancers and independent contractors.

In his view, a major problem is that many struggling workers are viewed as independent contractors and do not have many of the basic protections guaranteed regular workers, including the right to overtime pay and workers’ compensation.

Bhairavi Desai, executive director of the Taxi Workers Alliance, praised Mr. Ott’s strategy and agreed with his analysis.

“Unless we lift the floor, the ceiling is going to collapse,” Ms. Desai said. “Some of the mainstream labor movement is all about fending for yourself as opposed to working together to raise conditions across the board for all workers.”

Mr. Ott said several New York unions have become more serious about helping low-wage workers. He cited the United Federation of Teachers, which has unionized 28,000 home-based child care providers, as well as the Retail, Wholesale and Department Store Union, which has organized nearly 1,000 workers at H & M clothing stores in Manhattan. He also praised the efforts of Unite Here to raise wages for Aramark workers, who earn an average of about $20,000 a year in corporate cafeterias at Goldman Sachs, Bank of New York and other financial institutions.

“One of the dangers we have in this city is the city is polarizing economically,” Mr. Ott said. “There is some fabulous wealth toward the top. And there is this growing body of working-class folks. The middle could collapse. The danger is, are our standards not sustainable in a city’s that’s politically and economically polarized?”