New York City Mayor Michael Bloomberg and Maryland Gov. Martin O’Malley attend a gun violence summit at the Johns Hopkins Bloomberg School of Public Health in Baltimore on Monday. (Patrick Semansky/Associated Press)

If Maryland Gov. Martin O’Malley is willing to put his political clout behind instituting a new licensing requirement for gun owners, might he also support a 50 percent tax on bullets? How about mandating that gun owners purchase insurance on their weapons or giving the state police powers like federal agents to raid Maryland gun shops?

O’Malley’s announcement Monday that he would seek a sweeping package of gun-control legislation — almost a week before the bills are actually due to go before the legislature — has many liberal Maryland lawmakers hoping to include even more restrictive gun-control measures.

And if they can’t sway O’Malley (D), a handful of senior Democrats say they will introduce measures of their own and seek to amend the governor’s gun-control package as it moves through the Demo­cratic-controlled General Assembly.

“The governor’s package will be the heart of the action, and my focus will be on passing the governor’s plan,” Sen. Jamie B. Raskin (D-Montgomery) said. “But there will be a number of other bills out there.”

In one of the most expansive legislative responses proposed to last month’s school shooting in Newtown, Conn., O’Malley said Monday that he will seek to institute some of the nation’s strictest gun-licensing requirements, ban assault weapons and restrict visitor access to schools.

Look at gun homicides and gun ownership by country

Perhaps most controversially, O’Malley wants a new gun-licensing requirement that would force prospective gun owners to provide fingerprints to state police, complete a hands-on weapon-familiarization and gun-safety course, and undergo a background check before beginning the existing process of seeking a permit to purchase a weapon.

With Democrats firmly in control of both chambers of the legislature, however, the specter of O’Malley’s package becoming an unruly wish list for gun-control advocates could complicate the governor’s goals.

Sen. Brian E. Frosh (D-Montgomery), chairman of the powerful Senate Judicial Proceedings Committee and a possible candidate for attorney general in 2014, promised not to let that happen as the governor’s bills move through his committee. But he said he has asked O’Malley to support one additional measure: giving the Maryland State Police new authority to inspect the inventory of gun dealers. It’s a task now performed inadequately, Frosh said, by the federal Bureau of Alcohol, Tobacco, Firearms and Explosives.

In the past decade, a disproportionate number of firearms recovered at crime scenes in Maryland have come from a handful of the state’s gun dealers, a Washington Post investigation found in 2010. Frosh said he thinks that better inspections of and accountability for guns held by dealers would reduce crime. Frosh said that, regardless of whether such a provision is included in O’Malley’s legislation, he will seek to pass the measure, which cleared the Senate during the last 90-day legislative session but ran into resistance in the House.

“This is the year,” he said of achieving major gun-control reform. “If not now, when?”

Other lawmakers went further. Del. Jon S. Cardin (D-Baltimore County), another expected candidate for attorney general, said Monday that he will introduce legislation that imposes a 50 percent excise tax on ammunition and adds a $25 annual gun registration fee. The revenue would go to programs for mental health and the developmentally disabled.

Sen. William C. Ferguson IV (D-Baltimore) plans to push a bill that would make it more difficult to obtain a concealed weapons permit. It would also further restrict where concealed weapons could be carried.

Under current state law, Marylanders must show “good and substantial reason” to obtain a handgun permit from state police. But that restrictive standard could change. In March, a federal district judge ruled that language was unconstitutional. The state is appealing.

Raskin added that he would pursue a measure making it a misdemeanor not to report a lost or stolen firearm within 24 hours.

O’Malley aides said Monday they had mostly received positive feedback about the governor’s proposals and were unlikely to significantly change the package, the details of which were first reported by The Washington Post.

Aides said the governor is still weighing minor changes to his package, including whether to raise the age restriction for possession of ammunition and firearms to 21.

That’s far from the most liberal measure likely to be introduced. Ferguson vowed to seek passage of a measure requiring gun owners to have insurance on firearms in Maryland.

That plan has little chance of passage, Ferguson acknowledged, “but I think it will at least start a good discussion.”

John Wagner contributed to this report.