HARRISBURG - One week after Montgomery County began issuing marriage licenses to same-sex couples, the Corbett administration has filed a lawsuit seeking to block the practice.

The state Department of Health asked Commonwealth Court on Tuesday to issue an injunction to block D. Bruce Hanes from issuing any more licenses or accepting marriage certificates from gay and lesbian couples.

In response, Montgomery County said it would defend Hanes. Until a court intervenes, "the Register of Wills Office will continue to issue marriage licenses to same-sex couples," County Solicitor Ray McGarry said in a statement.

The lawsuit alleges that Hanes "risks causing serious and limitless harm to the public," citing "administrative and legal chaos" and couples "left to believe erroneously that they have entered into a valid marriage under the law of Pennsylvania."

State law restricts marriage to one man and one woman, and states that same-sex marriages performed in other states and countries "shall be void in this commonwealth."

Last week, Hanes announced that he would not enforce that statute because he believes it conflicts with equal-protection clauses in the state constitution.

The lawsuit means even more uncertainty for at least 34 couples who have received same-sex marriage licenses in Montgomery County. Typically, they have from three to 60 days to get a licensed officiant to carry out the weddings and return the certificates to the register of wills.

As of Tuesday afternoon, only six had completed their ceremonies and filed their marriage certificates. Whether those six couples are in fact married depends on whom one asks.

Hanes and the Democratic-led Montgomery County commissioners say the marriages are valid, arguing that the state constitution supersedes the 1996 Marriage Law.

Corbett; the Health Department, which collects marriage records and statistics from counties; and many registers of wills from other counties say the licenses were issued illegally and thus are null and void.

Upon hearing of the lawsuit, a few of the couples who have not completed the process rushed to find officiants, aiming to get their paperwork in before a court could act.

Nicola Cucinotta of Paoli said she was picking up her daughter when her minister called with the news. "He said, 'They're not going to stop. Bring it in.' " Cucinotta and her partner, Tamara Davis, were married Tuesday night and planned to be in Norristown first thing Wednesday morning.

They're still planning a ceremony with family and friends this weekend.

Hanes, a lawyer who was elected register of wills in 2007, would not comment on the lawsuit Tuesday. But last week he laid out the legal basis for his decision to buck the Marriage Law.

When a lesbian couple notified him of their intent to request a marriage license, Hanes said, he consulted with his solicitors and came to rest on the "inherent rights" and "equality" guaranteed in Article 1 of the Constitution.

"Those are provisions of the Pennsylvania Constitution which I think are diametrically opposed to the Marriage Law," Hanes said Wednesday. "Now, what am I to do? I took an oath."

Hanes said he also took into consideration the U.S. Supreme Court decision striking down the federal Defense of Marriage Act and Pennsylvania Attorney General Kathleen Kane's announcement that she would not defend the state's Marriage Law against an American Civil Liberties Union lawsuit.

In its request for an injunction, the Health Department said Kane's "personal opinion" and the Supreme Court's ruling have no bearing on what is happening in Montgomery County.

"No public pronouncement of an executive official - even the attorney general of Pennsylvania - declaring his or her individual legal opinion that a law is unconstitutional relieves a public official such as the clerk from his mandatory duty to comply with the law," state attorneys wrote.

Hanes' actions in turn have given the Corbett administration more ammunition against Kane, who they say is "simply wrong" and setting "a very troubling precedent."

In a letter Tuesday, James D. Schultz, the governor's general counsel, said his office would defend the Marriage Law against the ACLU suit, which argues that the state's refusal to marry same-sex couples or recognize such marriages from other states violates a fundamental right to marry as well as the Constitution's equal-protection clause.

But Schultz argued that Kane's decision effectively usurped the authority of the courts to decide on the constitutionality of the state's statutes. Schultz noted that no court has ruled on the constitutionality of Pennsylvania's Marriage Law. As a result, he said, Kane's declaration sets the stage for any attorney general to refuse to defend laws with which they personally disagree.

"This will create chaos and uncertainty," Schultz wrote, "not unlike what we are seeing in the unlawful actions of the clerk of the Orphans' Court of Montgomery County, who has cited the attorney general's public declarations as justification for his own refusal to enforce the law."

In an e-mailed response to Schultz later Tuesday, First Deputy Attorney General Adrian R. King Jr. disputed those contentions, saying Kane had made "not a personal determination but, rather, a legal determination" that the Marriage Law was unconstitutional.

"Just as discriminatory laws based on race, religion, gender, disability, and ethnic origin have been struck down by the courts one by one, so, too will the Marriage Law," King wrote. "In short, this is a watershed moment. It is certainly not the beginning of the 'chaos and uncertainty' you predict."

Hanes' actions are widely viewed as having immediate statewide implications, since gay and lesbian Pennsylvanians came to Montgomery County for licenses that could then be used for weddings anywhere in the state.

Inquirer staff writer Amy Worden contributed to this article.