Gov. Janet Mills is delaying action on dozens of bills passed by lawmakers this legislative session, including measures to ban untraceable firearms and to give the Wabanaki Nations exclusive rights to operate expanded online gambling.

Mills had 10 days from when lawmakers gave final passage of each bill to sign it into law. Monday was the deadline for the last bills passed by the Legislature, and since lawmakers have adjourned for the year, any unsigned bills will be held until the next time lawmakers come back in session for at least three days — likely in January. At that point, Mills would have the option to veto each bill or allow it to become law without her signature.

“The Legislature passed a significant number of bills at the end of session, and the governor takes seriously her constitutional obligation to thoroughly review all of them and to evaluate their implications on Maine people, Maine businesses and the Maine economy,” Mills’ office said in an emailed statement Tuesday.

“In order to meet that responsibility, she will continue to review these bills and gather more information, and she looks forward to acting on them at the beginning of the next legislative session.”

In total, 61 bills passed by lawmakers are being held by the governor. Just under 500 other bills became law this year, and the governor has issued five vetoes, all of which were sustained.

The held bills include LD 1126, which would ban so-called ghost guns and require serial numbers on firearms, and LD 1164, which would give tribes exclusive rights to offer online gambling games such as blackjack, roulette and poker.

Mills’ office did not say Tuesday if she had specific concerns with either of the bills, though her administration testified against LD 1164.

The director of the Maine Center for Disease Control and Prevention said the center is opposed to gambling expansions for health reasons, and the executive director of the Gambling Control Unit in the Maine Department of Public Safety also opposed the bill, saying the expansion isn’t warranted when Maine’s sports betting program is only in its second year.

If the bills do end up becoming law, it could be many months before they take effect. The Legislature is not scheduled to reconvene until January, although a special session could be called sooner. Any bills that become law after having been held would take effect during or after the later session.

An emergency measure would take effect immediately after the expiration of the third day, while other bills would generally become effective 90 days after adjournment. Neither LD 1126 nor LD 1164 is proposed as an emergency.

Lawmakers also have the option to recall held bills so they can continue to be worked on during the next session. Democratic leaders have already indicated they may do that with another bill, LD 1971, which would limit local law enforcement’s ability to work with federal immigration authorities. Mills, a Democrat, has expressed concerns about the bill being overly broad and confusing.

Rep. Sam Zager, D-Portland, the sponsor of the bill to ban untraceable firearms, said Tuesday that while he would have liked to see the measure signed, “it’s still very much alive.”

“I think (the governor) is probably being thoughtful and taking her time,” Zager said. “I also strongly believe this is a good move for Maine to take at this point with unserialized weapons.”

Others bills that are being held include LD 222, which would establish a take-back and disposal program for firefighting and fire-suppressing foam containing toxic PFAS chemicals, and LD 957, which would require schools to teach Asian American, Native Hawaiian and Pacific Islander history.

Also on the list is LD 1871, which would allow a person to petition for their criminal history to be sealed if the crime was the result of them having been a victim of sexual exploitation or sex trafficking.