One of New York’s Senate leaders faces a primary challenge next week in a key contest that could help determine which party controls the chamber next year.

Sen. Jeff Klein, who heads the five-member Independent Democratic Conference, is in a primary against Oliver Koppell, a former state assemblyman, attorney general and City Council member in a district that includes parts of the Bronx and Westchester County.

Klein’s group broke from fellow Democrats and partnered with Republicans to manage the Senate and determine which bills get to a floor vote. In June, under pressure from Democrats, Klein’s faction promised to end that power-sharing arrangement and align with traditional Democrats.

But Koppell said his opponent shouldn’t be trusted after keeping the Republicans in power for his benefit and effectively killing several Democratic initiatives, including further raising the minimum wage. “The fact is that Klein is the poster boy for pay-to-play,” he said, referring to Klein’s ability to raise campaign donations from big contributors.

Klein said voters should re-elect him because he helped send $300 million to New York City to fund full-day prekindergarten, pass new state restrictions on high-capacity gun magazines and raise the cap on the city rent freeze while breaking from the usual dysfunction to get budgets and bills passed. He said one example was raising the minimum wage to $9.

Klein is among 28 incumbents seeking another two-year term in the Legislature. The Board of Elections lists 21 Senate primaries, including 12 incumbents from the 63-seat chamber.

Another member of Klein’s independence conference, Sen. Tony Avella, has a primary challenge for his Queens seat from John Liu, the former New York City comptroller, City Council member and mayoral candidate.

Avella says he’s a reformer who brings independent thinking to the Senate. “I do what I think is right rather than just what the party politics tells me to do.”

Liu said he believes there are many statewide issues, including a package of 10 women’s equality bills, that have been “obstructed” by renegade Democrats like Avella who “have only empowered the Republicans.”

He also blamed them for blocking liberal legislation like the minimum wage. “It’s one common-sense measure that needs to be done yesterday to just start to bring the widening wealth gap back in line,” he said.

In other races:

— Two senators facing federal charges, both former leaders of the mainline Senate Democratic Conference, have primary opponents. Both have pleaded not guilty.

Sen. John Sampson of Brooklyn is challenged by Sean Henry, Elias Weir and Dell Smitherman. Weir also filed valid petitions for the Conservative Party ballot line, and Smitherman filed them for the Working Families Party line. Sampson is accused of embezzling $440,000 when he was a court-appointed referee watching over escrow accounts for sales of foreclosed properties. He’s also accused of funneling funds into his failed campaign for Brooklyn district attorney.

Sen. Malcolm Smith, a Queens Democrat, is challenged by Munir Avery and Leroy Comrie Jr., who has filed for the Working Families Party ballot line. Smith is accused of scheming to bribe Republican Party leaders so he could run for the GOP line in the New York City mayoral race. He faces trial next year.

In the 150-seat Assembly, there are 32 primaries, including 15 incumbents.

— Assemblyman Herman “Denny” Farrell Jr., a legislator from Manhattan for 40 years and chairman of the powerful Ways and Means Committee, is being challenged in a Democratic primary by community activist Kelley Boyd.

Boyd, a technology executive, said her campaign grew out of an overcharge claim against her landlord that went to New York’s highest court. She says Farrell’s office gave her little help with the claim. She says Farrell, who’s 84, isn’t in the district often and has stopped representing the people back home. “Nobody’s protecting us in those laws,” she said, citing predatory landlords and the check-cashing industry.

Farrell said he helps constituents with various issues, is in the district nearly every weekend at block parties and other events, and has worked to establish affordable housing, with access for people with limited mobility. He met with Boyd about her problem and put her in touch with housing officials, but she came to him too late to help her given the law, he said. “She picks the one issue I beat the crap out of anybody on,” he said, saying his record includes taking buildings away from landlords.

— Republican Assemblywoman Claudia Tenney from Oneida County, a lawyer who lost a congressional primary this year, faces a primary challenge for her Assembly seat from Christopher Farber, the Herkimer County sheriff.

(AP)