Legislation authorizing the unionization of in-home child care providers is under another legal challenge.

In a lawsuit against Gov. Mark Dayton and other government officials, the plaintiffs claim that the legislation violates the state and U.S. constitutions because only a fraction of the state's approximately 11,000 child care providers would be allowed to vote toward unionization. The 11 plaintiffs are asking a judge to permanently block implementation of the Family Child Care Providers Representation Act signed in 2013.

The suit, filed Tuesday in Ramsey County District Court, names as defendants Dayton; Josh Tilsen, commissioner of the Bureau of Mediation Services (BMS), and Emily Johnson Piper, commissioner of the Department of Human Services.

According to the suit: Only child care providers who were actively registered with the Minnesota Child Care Assistance Programs in the past 12 months and who received subsidies from the program in December 2015 can vote to determine whether AFSCME should represent child care providers.

That means only 2,348 providers can vote in an election that was announced by the BMS in January.

The legislation and unionization efforts will interfere with other child care providers' abilities to negotiate contracts directly with their clients, the suit said.

The suit is asking a judge to stop implementation of the act, to declare it unconstitutional, to stop BMS from conducting the election and to award the plaintiffs attorneys' fees and costs.