NORTH BAY — Kaiser Permanente employees across Northern California could have a chance to choose between two quarreling unions as early as next week.

The National Labor Relations Board in Washington is expected to issue a date in a matter of days for elections that would determine whether nearly 43,000 Kaiser workers would remain with Service Employee International Union-United Healthcare Workers West or join its rival offshoot, the National Union of Healthcare Workers.

As of press time, the NLRB had not set a date.

The two unions have been locked in a labor dispute over Kaiser and other health care facilities throughout the state, and the Kaiser elections could prove vitally important for both unions as each seeks to solidify its influence.

Over the past several weeks, SEIU-UHW has accused NUHW of delaying a vote that it sought, thus further dragging out the issue that SEIU-UHW says would be resolved by a prompt vote.

NUHW, however, said it has not refused a vote. Instead, the union said it disagrees on the grounds for voting proposed by SEIU-UHW, which would include a work-place vote. NUHW has petitioned the NLRB for a vote that would consist of mailed ballots versus the workplace vote.

Mail-in votes are common in the public sector. NLRB private-sector votes that include home-care employees also typically use mail-in votes because there is not a centralized workplace.

The vote would include thousands of medical assistants, respiratory therapists, medical records clerks and housekeepers across the region.

At Kaiser in Santa Rosa, about 1,250 employees would be included; in San Rafael, about 800; in Napa, about 120; in Fairfield, about 113; in Vacaville, about 550; and in Vallejo, about 1,900.

Should the election proceed, it will be the largest-ever election for a private-sector union in California history.

Oakland-based Kaiser has vowed to remain neutral in the elections.