A second legal challenge has been filed to block a home care unionization effort authorized by the Legislature and Gov. Mark Dayton.

A group of child-care providers, including Jennifer Parrish of Rochester, an active opponent of the attempt to organize in-home child-care providers, filed suit in U.S. District Court on Wednesday.

The complaint concerns a law passed on the last day of the session and signed by Dayton. It allows certain in-home child-care providers and personal-care attendants to vote on whether to unionize. Two unions, the American Federation of State, County and Municipal Employees (AFSCME) and the Service Employees International Union (SEIU), are trying to organize the providers and care attendants.

Wednesday's lawsuit concerns only the child-care providers. It argues that the law could force providers to be represented by a union they do not support, and to financially support the union as well.

"Plaintiffs strongly oppose being forced to accept or support a mandatory exclusive representative for purposes of petitioning the state," the lawsuit says. "They also do not want their individual right to choose with whom they associate for petitioning government to be subjected to a majority vote. Plaintiffs want to retain their individual right to choose with whom they associate to lobby the state over its child-care policies."

The suit asks the judge to declare the law unconstitutional and to prohibit it from going into effect. A similar lawsuit was filed last week in federal court.

Dayton said Wednesday that a judge threw out his union election executive order last year by saying the Legislature should decided the issue.

"The Legislature did exactly that, they did what they saw fit," Dayton said. "And now the groups are throwing their little fits and they are trying to throw sand into the machinery and delay."

He said the law gives providers the right to decide for themselves on unionization, adding, "We are not mandating anybody forming a union."

Dayton called the lawsuits "unfortunate," saying, "It's going to waste a bunch of taxpayer money to deal with the lawsuit."

The National Right to Work Legal Defense Foundation of Springfield, Va., said it is offering free legal help for the suit filed Wednesday. Dayton said of the legal challenges: "It's a very well-financed effort, which I have to believe it is national in its source."