FILE - A customer swipes a MasterCard debit card through a machine while checking-out at a shop in Seattle. (Elaine Thompson/AP)

The retail industry launched a new campaign Wednesday to protect a federal law that reduces the fees retailers must pay to banks every time a debit card is swiped, a move the industry hopes will blunt the massive lobbying attack from banks.

The campaign calls for hundreds of merchants to flood Capitol Hill in June for meetings with key lawmakers, the third “fly-in” to be held this year on the issue. It also includes print and radio ads in Washington and six to 12 key states, along with viral video clips. Industry executives say they expect the campaign to generate several thousand comments to lawmakers before the regulations on swipe fees, also known as interchange, take effect this summer.

“We’re going to raise the volume over the next 60 days,” said David French, chief lobbyist at the National Retail Federation, the trade group organizing the effort.

As part of the overhaul of the nation’s financial system last summer, Congress approved a measure that directed the Federal Reserve to revamp the way banks charge merchants for accepting debit cards. The Fed’s proposed regulations would lower the fees by as much as 70 percent, to 7 to 12 cents a swipe.

Financial firms from community banks to Visa and J.P. Morgan Chase have balked at the proposition and blanketed Capitol Hill with ads and advocates in recent months. Metro trains have been covered in ads. Visa recently convened a global security summit to highlight fraud-prevention technology that it says is supported by the fees. This industry is pushing several bills that would delay implementation of the law.

Sen. Jon Tester (D-Mont.), who sponsored one of the bills, said Wednesday that he is willing to shorten the proposed delay from two years to 15 months. That timeframe — which Tester called the “bare minimum” — would allow for six months to study the law, six months for regulators to draft new rules and three months for banks to implement them.

“I’m asking that we take a closer look so we can get the information to understand the impacts both intended and unintended,” he said.

The move was a bid to increase support for his proposal, which faces an uncertain fate in the face of vigorous opposition by Senate majority whip Richard J. Durbin (Ill.), who sponsored the original law. Retailers have said that waiting to implement the law is tantamount to killing it.

“This is a debate that has already happened,” French said. “Banks want a do-over.”

One NRF radio spot targets Tester directly, accusing him of allowing banks to “swipe our money.” The NRF said it has spent at least a million dollars to preserve the law, and the latest campaign is expected to cost several hundred thousand more. Though it acknowledged it could not match the coffers of the banking industry, French said the goal was to spend its money “in a consequential way.”

The amount of money at stake for both sides is even greater. According to the Federal Reserve, interchange fees totaled nearly $17 billion in 2009. Under the current system, retailers include those costs in the prices they charge to consumers, amounting to what they called a “hidden tax on shopping.” Any reductions in the fees would be passed on to consumers in the form of lower prices or better service, the NRF said.

But banks say they count on the fees to offset the cost of offering checking accounts and popular customer perks, such as debit card rewards programs. Several banks have already begun raising ATM and other fees in anticipation of the new regulations.

The law exempts banks with assets of less than $10 billion, though financial groups and government regulators acknowledge they may still see reduced fee income.

The Fed said it missed its self-imposed deadline last month for issuing its final regulations on the fees because it had to sift through 11,000 comments on its proposal. The law, which applies only to debit cards, is scheduled to go into effect July 21.