Republican presidential hopeful Chris Christie is supporting Texas and other states in their lawsuit over President Barack Obama's executive orders benefitting undocumented immigrants, the Associated Press reported.

The New Jersey governor signed onto an amicus brief -- a way for third parties to introduce concerns in a case -- urging an appeals court to uphold a preliminary injunction that blocks steps that could spare millions of people who are in the United States illegally from deportation.

In the document, the Lone Star and Garden states -- along with Louisiana and South Dakota -- argue that Obama's plan would cause them "irreparable injuries."

"The question presented is whether the President can unilaterally legalize the presence of millions of people and unilaterally give them myriad legal benefits, including work permits, Medicare, Social Security and tax credits," the brief noted. "Washington's attempt to turn this into a policy debate only underscores the dearth of legal arguments to support Defendants' unilateral efforts to hand out government benefits in violation of federal law," it added.

Although Christie has been critical of Obama's policies in the past, the governor has yet to outline his own positions on the nation's immigration system, the AP judged. His decision to take a public stance on the lawsuit pending before the U.S. Court of Appeals for the Fifth Circuit, meanwhile, surprised many in his home state, according to NJ.com.

Ari Rosmarin, the public policy director for the American Civil Liberties Union of New Jersey, noted that the Garden State is not a party to the original lawsuit and that its aims do not represent "New Jersey values."

"To see Christie enter himself as governor on to this brief with the likes of governors of Texas, Louisiana and North Dakota is really shocking and shameful," Rosmarin said.

A spokesman for Christie declined to comment but confirmed that the governor had signed onto the amicus brief, NJ.com detailed.

New Jersey Sen. Robert Menendez, a Democrat, meanwhile, defended the legality of Obama's actions and argued that many residents stand to benefit from the president's plan, the AP noted.

"Let's not forget that an estimated 204,000 people in New Jersey (would) be able to come out of the shadows and contribute to the community" Menendez insisted in a statement.