Bloomberg thinks he is "the public"

He is close to being off his head

NEW York Mayor Michael Bloomberg says he will invest $US12 million ($A11.5 million) in a nationwide ad campaign to counter the powerful US gun lobby and rally support for background checks in gun sales.

"We're running ads around the country. We have people manning phone banks and calling. We're trying to do everything we can to impress upon the senators that this is what the survivors want," Bloomberg told NBC's Meet the Press.

"I don't think there's ever been an issue where the public has spoken so clearly where Congress hasn't eventually understood and done the right thing."

He added: "If 90 per cent of the public wants something and their representatives vote against that, common sense says they are going to have a price to pay."

Wayne LaPierre, head of the powerful National Rifle Association, brushed off the billionaire mayor's plans, telling the same news program his group's members had already mobilised to oppose new gun control legislation.

Bloomberg is "going to find out this is a country of the people, by the people, and for the people. And he can't spend enough of his $US27 billion to try to impose his will on the American public," LaPierre said.

"We have people all over, millions of people, sending us $US5, $US10, $US15 cheques, saying stand up to this guy."

He said the NRA would support a better system of keeping records on the mentally ill and convicted criminals, as well as harsher penalties for individuals who use firearms to commit crimes.

Bloomberg has said he will focus his campaign on legislation to expand background checks, which is seen as having a much better chance of succeeding than an outright ban on assault weapons or high-capacity magazines.

SOURCE