Former New Hampshire state Rep. Gary Lambert (R), a Nashua-area attorney and member of the Marine Corps reserve forces, told The Hill he was considering a run for her 2nd-district seat in 2014.

"I am thinking of running," he said. "I'll be retiring on June 4, 2014, and I'd like to get back into politics when I retire."

Lambert said he was keeping his options open with respect to what specific race he might jump into, but that he had made it very clear to Republicans in New Hampshire that he was interested in challenging Kuster.

Kuster, a two-time candidate who was defeated in 2010 by Republican Charles Bass but went on to topple him in 2012, has been targeted by the National Republican Congressional Committee in a number of its early attacks. She won her race by only five percentage points, and President Obama won her district by a little less than 10 percentage points in 2012, making it a possible pickup opportunity for Republicans in 2014.

And she's faced increased scrutiny over the past few days due to a report from local news site WMUR that Kuster owes $11,000 in late property taxes on her two homes in New Hampshire.

Kuster issued a statement on Wednesday afternoon apologizing for the late tax payments and promising to deliver future payments on time.

"Our property taxes are paid in full with interest to the Town of Hopkinton. Payment for our rental property in Jackson is en route. I regret the delay and apologize for any inconvenience. All future tax payments will be delivered promptly," she said.

But the New Hampshire Republican Party is working to make an issue of the late taxes, issuing multiple releases on the situation and on Thursday sending one out with a statement from Lambert slamming Kuster for what he said was a failure to adequately explain the situation, and calling for her to release her tax returns.

"Congresswoman Kuster’s inability to explain why she was delinquent on more than $40,000 in property taxes is extremely troubling and raises serious questions that must be addressed immediately. The people of the Second District have a right to know why their elected representative in Washington deliberately refused to pay her fair share in taxes until the media caught her red-handed," he said.

New Hampshire Democratic Party Chairman Ray Buckley in a statement attempted to focus attention on recently-elected NHGOP Chairwoman Jennifer Horn's more than $90,000 tax lien, which WMUR reports has not yet been paid.

"I find unbelievable that the same party that just elected as Chair a person with a lien of over $90,000 for years of back taxes continue to keep unpaid taxes in the news. When Congresswoman Kuster became aware of her small back tax bill, she immediately paid it in full. When Chairwoman Horn's tax woes were revealed, she called it part of 'personal attacks on my family,'" he said in the statement.

--This post was updated at 2:48 p.m. to reflect comment from Kuster.