Democratic lawmakers say they will challenge a regulation adopted by Gov. Christie's administration that makes it easier to qualify for a gun-carry permit, although how they might seek to reverse the rule was not clear Tuesday.

The Democratic-led Legislature had previously voted to invalidate the rule change, which expands the criteria of what constitutes "justifiable need" -- the standard applicants need to demonstrate to get a carry permit. Despite the legislative action, Christie's office announced the adoption of the new rule Monday.

The Legislature's action "was procedurally deficient and substantively incorrect, and we expect to prevail in any challenge," said Brian Murray, a spokesman for the Republican governor.

The rule change allows police chiefs and the state police superintendent to consider whether a person applying for a gun-carry permit faces "serious threats" and whether the danger to a person's life cannot be avoided by other "reasonable" means.

Previously, applicants had to demonstrate specific threats, causing danger that couldn't be avoided by "any" other means. Gun-rights advocates had argued that standard was unreasonably narrow.

Without specifics, Democrats on Tuesday invoked the possibility of court action. Assembly Speaker Vincent Prieto (D., Hudson) said in a statement that "I will do everything in my power to make sure the governor's actions do not stand."

"We beat the governor in court when he tried to destroy civil service," Prieto said, referring to a decision striking down a rule adopted by Christie's administration enabling certain public worker promotions without competitive examinations. "We'll do it again when it comes to his threat to public safety."

In the Senate, Majority Leader Loretta Weinberg (D., Bergen), who sponsored resolutions to invalidate the gun-rule change, said that "the court has spoken on the Legislature's authority when it comes to exercising this process" and that "I am confident we are on firm legal footing."

The rule change was proposed by a commission Christie created in 2015 just before launching his presidential campaign. The governor has argued changes to the permitting system are needed, pointing to the 2015 death of a Camden County woman who was stabbed by an ex-boyfriend after a delay in response to her request of a gun permit.

While lawmakers passed two resolutions last year stating that the rule change violated legislative intent, the Republican governor's administration contends that action wasn't valid for procedural reasons.

The Legislature's argument also isn't valid, according to the notice of the rule's adoption by state police. The notice cites a 1990 New Jersey Supreme Court decision on the permit standard that refers to "an urgent necessity for protection of self or others" existing in cases of "serious threats."

According to the 1990 decision — In re Preiss — the statutory standard "calls for a permit to be issued only to those who can establish an urgent necessity for protection of self or others as for example, in the case of one whose life is in danger as evidenced by serious threats or earlier attacks."

Previous battles between Christie and the Legislature over regulations have taken time to resolve. The civil service rule change struck down by the appeals panel in December was adopted by Christie's administration in 2014.