About 73 percent of likely Miami-Dade voters oppose a Miami Dolphins tax-break plan for stadium improvements, according to a new poll obtained by The Miami Herald that indicates the issue is politically damaging for lawmakers.

The poll was instantly criticized by the Dolphins management and lobbyists Wednesday just after the club’s plan won unanimous approval from a state Senate committee in Tallahassee to cover nearly half of the $400 million stadium improvements.

But legislators knew SB 306 faced tough times in the anti-tax Legislature, so they amended the bill to require a local referendum.

If it makes the ballot, the plan will be killed by Miami-Dade voters, said pollster Dario Moreno.

“This is toxic to the Legislature, the county commission and the executive,” Moreno, a Florida International University political scientist said.

Opposition to the plan cuts across racial, ethnic, party and geographic lines, according to the poll of 1,000 voters taken Monday and Tuesday.

“There’s not one group of likely voter who supports this idea,” he said. “Even in County Commission District 1, where the stadium is, people are overwhelmingly opposed.”

State Sen. Oscar Braynon, a Democrat who represents the stadium’s hometown of Miami Gardens, said the deal will bring jobs.

“This is going to be a great economic boon to my community and to the state of Florida,” said Braynon.

To make sure that happens — and to prevent a veto should the bill pass the Legislature — Gov. Rick Scott issued five guidelines Wednesday he will use to approve the stadium deal. He wants a study to review the cost to be sure the Dolphins pay their fair share.

“The most important thing is I’m responsible to make sure taxpayer money doesn’t get wasted and so, if we can get a return on those dollars, then that’s important to me. I want to do the right thing for taxpayers,” Scott told the Herald/Times on Wednesday.

The Miami Dolphins say they’re already on the path to meeting those goals.

The club’s president and CEO, Mike Dee, also issued a written statement suggesting that the poll Moreno asked misleading or unfair questions.

“A ginned-up poll paid for by a mystery client that goes out of its way to lead people to a negative position is hardly enough to sway us from our efforts to put this issue in front of voters this spring,” Dee said.

However, Moreno’s poll wording appeared straightforward. Moreno also gave The Herald access to the so-called crosstabs of his polls that indicate the sample size, questions and responses by party and race.

The Dolphins shared only one result from one of their polls, conducted by a group called OnMessage Sports, that showed 59 percent of voters approved of the plan and 33 percent of voters disapproved. The poll’s website indicates its polling company is OnMessage media, which worked for Scott’s 2010 campaign for governor and his anti-Obamacare effort before that.

But the club didn’t share its crosstabs and the favorable result came from a so-called “message-testing” poll where voters are given leading information — the very type of technique the Dolphins criticized Moreno for using. They also called him “Norman Braman’s pollster,” because Moreno has worked for the outspoken car dealer who has used his millions to oppose publicly financed stadiums and the politicians who support them.