Two Christian churches on Wednesday filed a legal challenge in federal court to Hawaii's civil unions law, claiming it's unconstitutional, Courthouse News reported.

Governor Neil Abercrombie signed in February the legislation that gives gay and straight couples nearly all of the legal protections of marriage. The law is set to take effect on January 1.

(Related: Gay couples to enter civil unions at midnight on New Year's Eve in Hawaii.)

The law violates the civil rights of clergy and churches because it does not exempt them from hosting such ceremonies, the lawsuit claims. (The law does exempt clergy from solemnizing a civil union for any reason.)

“Neither Act 1 not it's [sic] implementing regulations exempt religious institutions, churches and houses of worship, clergy, officers and members from being subject to the injunctive relief and fine provisions of H.R.S. 489,” the complaint says. “Within the last 12 months, private individuals have already initiated complaints with the Hawaii Civil Rights Commission against churches and houses of worship for refusing to rent their facilities for same-sex unions and/or marriage ceremonies.”

The plaintiffs – Emmanuel Temple, Lighthouse Outreach Center Assembly of God and its pastors – are asking the court to declare the law unconstitutional.

(Related: Lesbian couple sue for right to marry in Hawaii.)