Jaime Contreras, of the SEIU, speaks at the Arlington announcement of a labor and minority coalition on May 18. (Patricia Sullivan/The Washington Post)

A coalition of labor and minority groups is launching an effort to support progressive Democrats running in Virginia’s June 9 primary election and has promised five candidates a last-minute infusion of cash and a small army of door-knocking volunteers.

Coalition leaders said they will try to mobilize young and minority residents who have not voted in large numbers in the past and urge them to back local candidates who want to boost the minimum wage, expand health-care coverage for the poor, and create new protections and opportunities for immigrants.

After the primary, the group said, it would continue to try to turn out that segment of the electorate to help progressive candidates in the general election.

“It would be a mistake to think this generation is apathetic,” said Austin Thompson, the coalition’s head of African American and youth outreach effort. “But no one is talking to these voters across the state, and that has to change.”

Although organized labor has been a factor in statewide races in Virginia for several years, political scientists said local contests are a new and potentially valuable battleground.

“Especially if they are reaching out to Latinos, because that’s where the population is growing,” said Derek Hyra, director of American University’s Metropolitan Policy Center. “In Northern Virginia, the Hispanic and Asian population is more educated than in other areas around the country — and that’s an opportunity.”

On Monday, the group endorsed Christian Dorsey and Katie Cristol for the Democratic nomination in the Arlington County Board race. They are in a six-way primary battle for two seats in which many of the candidates identify themselves as progressives. The coalition said it chose Dorsey and Cristol because “they understand the struggles of working families” and have committed to minimum wage increases, Medicaid expansion and other issues important to the group.

The coalition also endorsed Penelope A. Gross (D-Mason), who has two challengers for the Fairfax County Board of Supervisors. The group also weighed in on two state legislative races. It endorsed Sen. Rosalyn “Roz” Dance (D-Petersburg), who faces challenger Joe Preston and could face disgraced former delegate Joseph D. Morrissey in the general election. The group also endorsed Steve Heretick, a lawyer and city council member from Portsmouth who is challenging incumbent Del. Johnny S. Joannou, a conservative Democrat from Portsmouth.

Republicans control both houses of Virginia’s General Assembly, although the state voted twice for President Obama, and Democrats have made inroads in statewide elections in recent years.

In the legislature and on county boards, incumbent Democrats range from conservative to liberal. Joannou, for example, was the only Democrat to join Republicans last year in rejecting Democratic Gov. Terry McAuliffe’s proposal to expand Medicaid coverage in the state.

At the same time, the state’s nonwhite population has grown, from 23 percent in 1990 to 31 percent in 2010. One of the most diverse areas is Northern Virginia.

Forty-two percent of Fairfax County’s 1.1 million residents are Asian, Latino or African American — an increase from one-third of the county’s population in 2000. During the same period, the number of foreign-born residents grew from about one-fifth of the population to nearly a third.

Twenty-eight percent of Arlington County’s 216,000 residents are young adults between the ages of 24 and 35, a jump of 3 percent, or 33,000 people, since 2000.

The labor groups in the coalition — two locals of the Service Employees International Union, a United Food and Commercial Workers local, and the Mid-Atlantic Laborers Union — represent tens of thousands of workers in Northern Virginia, many of them Latino. The other groups are the Latino advocacy group CASA in Action and the National Korean American Service and Education Consortium in Action Fund.

“One in nine Virginia residents are immigrants, and almost half can vote already,” said Gustavo Torres, president of CASA in Action, which launched in Arlington 18 months ago. He said his aim is to create a left-wing version of the tea party in what he likes to call “the new dominion” of Virginia.

“For a long time we have been setting the table,” Torres said. “Now, we want to sit at the table.”

Each of the five organizations in the coalition promised $2,000 in donations for the endorsed candidates, said David Allison of the Alexandria-based local of the laborers’ union, which is more than 70 percent Latino.

The infusion of cash could be significant for some of the local campaigns. In the most recent filings in the Arlington board race, for example, Cristol reported raising $25,906 and Dorsey reported $13,880 in donations.

Just as important as the money, however, is the fieldwork, Allison said. Up to 40 volunteers per candidate will knock on doors each of the next two weekends, trying to convince people who typically vote only in national or general elections that it is worth their time to come out for the primary.

“This coalition represents the changing face of Northern Virginia,” said Jaime Contreras, vice president of the SEIU Capital region. “Together we are much stronger than alone.”