SAN JOSE — Labor favorite Tim Orozco appeared headed to a runoff in the race to fill the open City Council seat in San Jose District 4 on Tuesday night. But just who he would square off against in that contest was anyone’s guess.

With an estimated 86 percent of the votes counted in the special election, Orozco held a small lead, with 1,855 votes, or 22.2 percent of those cast. Meanwhile, Manh Nguyen and Lan Diep, both backed by the local chamber of commerce, were seven votes apart in the race for second place. Only the top two candidates will compete in a runoff election June 23.

Late Tuesday night, Nguyen had 1,591 votes, or 19 percent, while Diep had 1,584 votes, or 18.9 percent. Among the seven other candidates on the ballot, no one had more than 950 votes or 12 percent of the total.

The next vote count update is expected to be announced at 5 p.m. Wednesday, according to he Santa Clara County Registrar of Voters website.

The special election was being held to fill the place held by Kansen Chu, who left the council for the state Assembly at the end of last year. The outcome of the race could determine the balance of power in City Hall, which right now is fairly even between business and labor supporters.

Those two interests groups hand-picked the candidates they hoped would tip the City Council in their favor. The local chamber of commerce supported both Diep and Nguyen. The unions supported Orozco, a policy aide for labor-backed state Sen. Bob Wieckowski.

Both Diep and Nguyen promised to add police officers and improve public safety during the campaign but differed in how to do it. Orozco would appease the police union by settling the lawsuit it has filed against voter-approved pension reform, a measure that has driven cops away to other cities. He also wanted to attract more businesses to San Jose and use the added revenues from the economic uptick to give officers better compensation.

Diep aligned himself with Mayor San Liccardo and other pension reformers who would rather use the money saved from employee retirement benefits to hire more cops. He believes voters still want the pension cuts after originally passing the initiative, called Measure B, in 2012.

Nguyen, a journalist who enjoyed strong support form the district’s Vietnamese community, focused his campaign on improving the city’s tax base.

The winner will take over the remaining 1½ years of the term vacated by Chu.

District 4 sits at the northeastern end of the city bordering the bay, Milpitas and Santa Clara, and includes the large, middle-class Berryessa and small, working-class Alviso neighborhoods. About two-thirds of the district’s 100,000 residents are Asian. The city’s first BART station is under construction and an expanding row of office parks is turning the district into a prime economic engine outside of downtown.

The other candidates included:

Bob Dhillon, who rallied support from the Indian community. He agreed with Liccardo’s pension plan to fund cops and supported the mayor’s radical idea to start the city’s spending plan each year from scratch to figure out what spending is really required. He had 941 votes, or 11.2 percent of the total.

Khoa Nguyen, a police officer and Berryessa Union School District board member, who had 651 votes, or 7.8 percent.

Alex Torres, an economic development consultant, who had 480 votes, or 5.7 percent.

Rudy Nasol, a San Jose-Evergreen Community College District Board member who ran an almost entirely self-funded campaign; he had 427 votes, or 5.1 percent.

Business owner Johnny Lee, with 309 votes, or 3.7 percent.

Allen Chiu of Congressman Mike Honda’s office, who had 276 votes, or 3.3 percent.