The political fight over pension reform is about to get bloody.

New York’s powerful AFL-CIO is mobilizing its 2.5 million union members to oppose Gov. Cuomo’s plan to overhaul pensions for future city- and state-government workers.

“We’re not looking to have a race to the bottom,” said state AFL-CIO President Mario Cilento.

But Cuomo, during a Post editorial board meeting yesterday, said he’s ready to battle with the unions to rein in runaway pension costs. “How they can be against adjusting future benefits just boggles my mind,” he said. “It’s just unbelievable to me.”

Meanwhile, a pro-Cuomo business group called The Committee to Save New York indicated it’s ready to spend millions of dollars on the airwaves to help win support for the governor’s plan.

Cuomo’s plan, backed by Mayor Bloomberg, would add a new pension tier for new government workers that would raise the retirement age to 65 from 62. It would also increase pension contributions paid by workers.