It is one of the most popular destinations with Britons looking for sunshine and glamour, but tourists thinking of going to Florida are being warned off by a US gun-control group.

The Brady Campaign to Control Gun Violence, named for a Reagan aide who was shot in the head during an assassination attempt on his boss, has released a series of adverts telling would-be tourists they could be putting their lives at risk because of new laws which come into force today, allowing Floridians to shoot an attacker in the street and face only a minimal risk of prosecution.

The adverts will appear in British newspapers this weekend, highlighting new laws affecting the state's six million gun owners. The ads read: "Thinking about a Florida vacation? Please ensure your family is safe. A new law in the Sunshine State authorises nervous or frightened residents to use deadly force.

"In Florida, avoid disputes. Use special caution in arguing with motorists on Florida roads. Police and prosecutors are concerned about the potential for unnecessary violence."

The Brady campaign is run by James Brady, who received a gunshot wound to the head in the attempted assassination of President Reagan in 1981. In 1993, his campaigning was rewarded by Bill Clinton, who signed the "Brady Bill" which imposed restrictions on hand-gun purchases.

Activists will also be handing out leaflets to Britons arriving at Miami and Orlando airports from next week, warning them to be cautious. About 1.5 million Britons visit Florida each year, attracted by its hot weather, coast and locations such as the Kennedy Space Centre and the theme parks in Orlando.

Sarah Brady, who heads the campaign, said: "We think people visiting Florida should be aware of this law, and act accordingly. Visitors should be very careful about getting into an aggressive argument with anyone during their stay."

The controversial new law, supported by the National Rifle Association, has been dubbed Shoot First by critics who fear it will lead to reckless gunplay on the streets. Before the law was passed, Floridians could carry concealed guns in public places but could only use them as a last resort when there was no other way to avoid injury.

The new law eliminates the need to avoid such threats by allowing the gun user to "shoot first".

Visit Florida, which promotes tourism in the state, branded the campaign a "scare tactic".

A spokesman said: "We believe that Americans and international visitors are smart enough to understand the political agenda behind the Brady Campaign and recognise that is not a real safety issue for visitors. In fact, Florida has a low crime rate, currently at a 34-year low, and it has been falling for 13 consecutive years. Florida is a very safe and secure destination that excels in caring for its visitors."

Keith Betton, a spokesman for the Association of British Travel Agents, said he did not think the adverts would have any impact.

"If they're trying to scare people, I think they've just wasted an awful lot of money," he said. "This law is not going to put people off travelling to Florida."