President Barack Obama on Wednesday will appoint Vice President Joe Biden to lead a panel tasked with devising new policies to address gun violence after last week's school massacre, a White House official said.

The official told AFP Obama would formally name Biden to spearhead the interagency panel at a White House event later in the day. The president is not expected to unveil any new policy decisions during the announcement.

Instead, the panel will attempt to frame new policies after the shooting in Newtown, Connecticut, in which a disturbed 20-year-old shot his mother, then 20 first graders and six staff at Sandy Hook Elementary School.

The panel is expected to carry out a broad study into gun violence in America, including looking at mental health policies and violence in popular culture and what can be done to beef up gun control legislation.

Obama vowed to take action against gun violence when he spoke at a memorial on Sunday for the victims.

On Tuesday the president backed a new bid to revive an assault weapons ban and other new gun laws, as traumatized US politicians wrestled with the aftermath of the worst in a series of mass shootings over the last two years.

The massacre shocked the country, and may have shifted the political debate on firearms in US society after years of gun lobby ascendancy.

But once outrage from the Newtown massacre fades, prospects for any new law remain uncertain and every piece of legislation is subject to intense amendment and pressure from various lobby groups.

The most well known gun lobby group, the National Rifle Association, spoke up about the school carnage for the first time Tuesday, saying it was "shocked" and planned a news conference for Friday.

Senator Diane Feinstein has pledged to put forward a bill early next year that would ban by name at least 100 military-style semi-automatic assault weapons, and would curb the transfer, importation and the possession of such arms.

White House spokesman Jay Carney said Obama would also be interested in any move to ban high-capacity clips -- magazines that hold dozens of rounds -- and to close the so-called "gun show loophole" that allows unlicensed individuals to sell guns privately.

The right to bear arms is enshrined in the Second Amendment to the US Constitution, and many political leaders are pro-gun for political and philosophical reasons -- but the political winds may be shifting.

West Virginia Senator Joe Manchin, a pro-gun politician, has given indications he may now back an assault weapons ban, and he may be a useful ally in the days ahead.

But several leading Republican senators were not ready to commit this early to specific anti-gun legislation or to rule out gun ownership altogether.

America has suffered an epidemic of gun violence over the last three decades, including 62 mass shooting sprees since 1982, three of the deadliest in the second half of this year alone.