A new group is launching a campaign to educate New York government workers about their rights to opt out of paying union dues following a US Supreme Court ruling.

The high court’s 5-4 decision last week blocked public-sector unions from collecting fees in lieu of dues from non-union members.

The group, New Choice NY, is now advising union members of their right to stop paying regular dues, as well non-union members who had been forced to cough up so-called “agency” fees.

“Want to exercise your right to stop paying dues? Use this form,” the group, an affiliate of Americans for Fair Treatment, proclaims on its website in guiding government workers how to quit their unions.

Americans for Fair Treatment’s three-member board includes the CEO of the right-leaning Commonwealth Foundation in Pennsylvania, which is backed by ­donors linked to the anti-union billionaire Koch brothers, The Philadelphia Inquirer reported.

New Choice NY spokesman Bob Bellafiore insisted his group is about providing workers “factual information” about their rights, not busting unions.

“It doesn’t matter to us if workers decide to stay with a union or leave. We believe New York’s public employees, armed with straight facts, are smart enough to make good decisions for themselves,” Bellfafiore said.

Labor leaders said they are prepared for the anti-union offensive.

Mario Cilento, president of the 2.5-million-member New York State AFL-CIO, claimed New Choice NY is part of a national ­anti-labor drive.

“The cork is out of the bottle. This is an orchestrated attack on the labor movement. If they think they’re going to dupe or trick hard­working union members, they have another thing coming,” ­Cilento said.

Transport Workers Union President John Samuelsen said the ­Supreme Court decision was a water­shed moment for labor.

“This is very much a ‘who are you with?’ moment — are you with the brothers and sisters in the ­labor movement or are you with the bosses who are trying to kill us?” he said.

State Comptroller Tom DiNapoli said last week his office would stop collecting union fees from 31,000 government workers covered by the high court’s Janus v. AFSCME ruling.

The Empire Center released a report earlier this year estimating that such a decision could cumulatively cost New York’s numerous public-employee unions as much as $112 million a year.