Gov. Andrew Cuomo’s proposal for a optional payroll tax continues to hit a speed bump with Republicans in the state Senate, who want more details on the proposal and doubt it can get doubt by the time the budget is expected to pass at the end of March.

“I mean, my visceral reaction is I think all of our colleagues are opposed to it,” Senate Majority Leader John Flanagan said Tuesday morning at a press conference unveiling his conference’s package of tax cut and regulatory reform proposals. “But the governor’s putting it out there and that’s his prerogative. We don’t have to agree with it. Do I think it can get done by the end of March? No.”

Cuomo’s payroll tax was unveiled this week and is meant to act as a workaround for the federal cap on state and local tax deductions set at $10,000, part of the December tax law approved by Congress. The tax is expected to be part of Cuomo’s 30-day amendments to his $168 billion spending plan.

The tax would be optional, phased in over three years, subject employers to a 1.5 percent tax on payroll expenses and eventually grow to 5 percent. Business could opt in by Oct. 1 and it wold take effect by January 2019.

Flanagan was skeptical the tax would be truly optional for businesses, which can still deduct state and local taxes without a cap on their federal filings.

“We need to see the details because sometimes voluntary is not voluntary,” he said.

Cuomo has railed against the federal tax law for its impact on New York and other high tax states that are dominated by Democratic voters.

Flanagan said he would have voted against the law and added he did like the measure itself. But he acknowledged the tax reductions in the bill has some benefit to other parts of the state outside of the metropolitan region.

“The true net effect: There’s a rigorous and vigorous debate as to whether it’s $14 million,” Flanagan said. “It certain parts of our state, the federal tax plan is far more beneficial — which is good. Where I live, it stinks.”