A recent poll has found widespread opposition to a proposed constitutional amendment to raise the state sales tax to benefit wildlife habitat, waterways, parks and the arts. However, proponents of the amendment said the poll was flawed and contradicted earlier surveys showing support for the measure.

Seventy-two percent of respondents to the Minnesota Public Radio/Hubert H. Humphrey Institute of Public Affairs poll said that increased arts and outdoors services should be paid out of existing revenues or by users, while 22 percent said the amendment is necessary to maintain the state's quality of life.

The poll of 763 likely voters was taken over an 11-day period ending Aug. 17. The margin of sampling error is plus or minus 3.6 percentage points.

Ken Martin, campaign director for Vote Yes Minnesota, a coalition of 200 groups supporting the measure, said the MPR/HHH poll didn't put the actual ballot question to respondents.

"They gave voters a false choice between taxes and existing revenues, and by offering that false choice and not leading with the ballot language, it skewed the results," he said.

Phil Krinkie, director of the Taxpayers League of Minnesota, said the new poll accurately reflects general opposition to the amendment.

"Am I surprised at the numbers? Somewhat, but it doesn't fall outside the bounds of what I'd be thinking," he said.

If approved by voters in November, the amendment would raise the state sales tax by three-eighths of 1 percent, bringing in about $270 million annually for 25 years.

One-third would be used to improve fish and wildlife habitat, and another third to clean up the state's lakes and rivers; one-fifth would go for the arts and cultural heritage, and about one-sixth would go to parks and trails.