New York’s largest public-sector union, the Civil Service Employees Association, is picking the lock on the state treasury.

And cynical Senate Majority Leader Joe Bruno is happy to help.

CSEA, among others, is trying to shield public-sector retirees from even the slightest touch of budget pain – no matter how much everyone else in New York has to suffer.

It’s pushing a bill that would lock in public-sector retirees’ health benefits for at least a year, with every expectation of annual repeats . . . forever. (A Post editorial and a column by fiscal expert E.J. McMahon warned about it Monday.)

No wonder the New York State Association of Counties “strongly opposes” the bill, saying it “eliminates potential cost savings options of local governments desperately seeking” to make ends meet.

No wonder the Business Council of New York State, representing taxpayers, is likewise sounding alarms. The bill, the council says, tells officials that their “only choice going forward is to raise taxes,” rather than “find reasonable ways to reduce the costs.”

And what’s CSEA have to say about that? We don’t care. We come first.

No kidding. Its president, Danny Donohue, says his aim is to make sure “localities live up to their responsibility to retirees.” And, he says, labor wants New York to do “what’s morally right.”

What a topsy-turvy view.

Unlike most folks, public employees generally pay little to nothing toward their health-care costs, either when they’re still working or after they’ve retired.

And while other New Yorkers struggle to maintain their own health benefits, CSEA’s view is: We’re special.

But then, how “moral” is it to force struggling homeowners to pony up ever-higher shares of their hard-earned income to pay off-the-chart property taxes? Or to ask firms (which provide jobs) to absorb more and more cash?

Still, for sheer cynicism, Bruno may top even the CSEA.

He and his Senate GOPers pretend to be the taxpayers’ champions, but – facing a tough November election – they’re just as ready to do the union’s bidding as are their Democratic peers: The Senate is set to pass the bill soon.

Bruno should tread carefully. Why, after all, would Republican voters back him and his GOP cohorts – when they’re no better than Democrats?

If the Senate does pass the bill, Gov. Paterson needs to follow the example of his two predecessors, Democrat Eliot Spitzer and Republican George Pataki, and veto it.

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