One of the state’s most powerful lobbying groups began a campaign Monday to block legislation that would give counties the power to tax real estate sales, arguing the tax would harm working families.

The N.C. Association of Realtors began running radio and television ads in major North Carolina media markets against the so-called “home tax.” The ads counter increased interest among some legislators who are trying to find new revenue sources for infrastructure needs in growing areas of the state.

“You work hard, you save up and buy a house. The American dream, right? So why do Raleigh politicians want to tax that dream when you sell your home?” a woman asks in a television commercial. “This home tax is a bad idea.”

Several bills introduced this legislative session would allow counties to assess a land transfer tax generally equal to a maximum of 1 percent of the value of the property, paid by the seller. The tax would have to be approved by county commissioners or by local voters through a referendum.

At least two legislative committees have been debating the idea. Supporters see it as a way to provide a new revenue source for county and city governments that contend they can’t keep up with demands new subdivisions place upon roads, schools and sewer systems.

“The land transfer tax would be a big boost to cities and counties, no question about it,” said Rep. Mickey Michaux, D-Durham, who has long supported giving local governments the power to initiate new taxes and fees. “As strapped as they are for money ... they’re going to have to have some outlets instead of coming to us.”

The 42,000-member N.C. Association of Realtors, which represents most of the state’s active residential real estate agents, argues in its ads and on the Web site www.itsabadidea.org that the proposed tax would reduce home affordability, strip homeowners’ equity and punish longtime residents who aren’t to blame for growth.

A land sale on property valued at $200,000, for example, would incur a tax of $2,000.

“We feel like it’s really important to get the message out to the public,” said Tim Kent, the association’s executive vice president. “A transfer tax is a tax on home sellers, people who already live (there), people who are already paying taxes.”

Any tax also would apply to sales of commercial real estate and land tracts.

Seven eastern counties already have received special approval from the General Assembly to assess a 1 percent land transfer tax, with proceeds going to local capital needs.

“It’s a tax that’s targeted to growth and it’s easily implemented,” said Rebecca Troutman with the N.C. Association of County Commissioners, which supports giving counties a menu of local option taxes, including one for land sales.

If all of the state’s 100 counties issued a 1 percent transfer tax, they could collect up to $600 million annually, a legislative researcher told a special House committee earlier this year. The committee ultimately declined to recommend the land transfer tax option after criticism from the development industry.

A separate tax reform commission is weighing a similar land transfer tax.

The state and counties already share a deed stamp tax of 0.2 percent on real estate sales.