ST. PAUL — The state board that regulates political spending in Minnesota finalized new reporting guidelines Tuesday for private donations to ballot measure campaigns, a decision with implications for next year’s statewide vote on a gay marriage amendment.

The state’s Campaign Finance and Public Disclosure Board approved a new “statement of guidance” on political spending for ballot measures that identifies some instances in which private donations to national groups trying to influence Minnesota ballot measures must be reported by the recipients of the donations. The vote angered socially conservative groups pushing for the ban on gay marriage in the Minnesota Constitution, and a spokesman for that coalition said the groups weren’t likely to follow the new guidelines.

Cleta Mitchell, an attorney for the anti-gay marriage group National Organization for Marriage, said a requirement for that level of disclosure can’t be found in state law and might in some cases discourage donors from giving to groups entering Minnesota’s marriage amendment fray out of fear of a backlash against their political views.

“They call those of us who support traditional marriage hate-mongers,” Mitchell said, adding many donors are afraid to be publicly identified.

Minnesota for Marriage, a coalition of socially conservative Minnesota groups pushing in for the constitutional gay marriage ban, announced after the campaign board meeting that it would follow current disclosure requirements in state law but it considered the new guidelines “illegal.”

Gary Goldsmith, the Campaign Finance Board’s executive director, said repeatedly that the new guidelines don’t alter state law but rather interpret it. But he said reports of groups running afoul of the guidelines could prompt enforcement actions by the board, which can carry hefty fines.

Goldsmith also said he believed the guidelines left many circumstances in which donors to groups like NOM wouldn’t have to be disclosed. Indeed, Mike Dean, the director of Common Cause Minnesota — which supports strict campaign finance reporting — had criticized the proposed guidelines for being “unnecessarily confusing” and lacking in clarity.

Mitchell said she expected legal challenges to the new guidelines but that might have to wait until the board attempts to enforce them.

Dean said he is worried the could mean the issue won’t be settled until after next November’s gay marriage vote and significant spending on that ballot measure campaign could continue to be unregulated.