The National Rifle Association (NRA) opens its annual meeting in gun-friendly Texas on Friday with its leadership determined to fight off any fresh attempt to tighten the nation's gun laws.

More than 70,000 people are expected at the three-day gathering in Houston, taking place a little over two weeks after the US Senate rejected President Barack Obama's proposal for universal background checks on gun buyers.

"The NRA doesn't do pep rallies," said NRA spokesman Andrew Arulanandam, dismissing suggestions that the 142nd NRA convention will be a time for celebration.

"We're engaged in a long battle (against gun control advocates) that will take years," he was quoted as saying in the Houston Chronicle newspaper. "We know it's not over."

Guns soared to the top of the US political agenda after the December massacre of 20 children and six educators at Sandy Hook school in Newtown, Connecticut by a young adult with a military-style semi-automatic rifle.

While Obama responded with a vow to implement tougher gun laws, the NRA -- which regards itself as a defender of Americans' constitutional right "to keep and bear arms" -- suggested more armed guards in schools.

Critics of the NRA, one of the nation's most powerful lobbying organizations, plan to turn out in force in Houston to remind its members that more than 30,000 deaths in the United States every year are gun-related.

They're planning a non-stop reading of the names of victims of gun violence since the Newtown shootings, as well as a press event with US military veterans who disagree with NRA policy.

"What would be a measure of success is how we increase public understanding of what the NRA has become, that they are a trade foundation for the gun industry," said Josh Sugarmann, of the Violence Policy Center in Washington.

"It's very important that this insular world the NRA has created, which is ofttimes a fantasy world, comes face-to-face with the reality of gun violence in this country," he said in a conference call with journalists.

Josh Horowitz, of the Coalition to Stop Gun Violence, rejected the NRA's description of itself as "America's longest-standing civil rights organization," saying it has become a soap box for the American far right.

"In addition to gun industry executives, the (76-member) NRA board of directors is populated with people who are hard-core insurrectionists and hostile to the values that make this country great," he said.

Big-name NRA supporters such as former Alaska governor Sarah Palin and former Republican presidential contenders Rick Perry (the current Texas governor) and Rick Santorum are to attend an NRA "leadership forum" Friday.

The main event Saturday is the "annual meeting of members," with speeches by NRA chief executive Wayne LaPierre and chief lobbyist Chris Cox, among other NRA executives.

"You could be part of an historic event like (actor) Charlton Heston raising a rifle over his head and saying those five unforgettable words ... "from my cold dead hands" at the 2000 NRA convention, the event's website says.

Running alongside this weekend's convention is a gun fair with more than 550 exhibitors including gun manufacturers, hunting outfitters and collectors of antique firearms.

There's also an air-gun shooting range for youngsters -- a likely target for NRA critics after a five-year-old boy in Kentucky shot and killed his two-year-old sister this week with a .22-caliber rifle marketed for children.