TORONTO -- Canadians on both sides of the border expressed surprise and indignation Thursday upon learning new rules require them to have an International Driving Permit to motor around the Sunshine State.

But as word of the change began to circulate, officials in the state that millions of Canadians visit every year issued a release saying enforcement was being deferred because the change may run afoul of an international treaty.

Under the rules introduced Jan. 1, all visitors with foreign licences must have an international permit issued by their country of residence in addition to a valid licence from home.

The quiet implementation of the regulations -- which apply to any vehicle, including rentals -- resulted in many Canadians being caught off guard.

"I had no idea, we've been coming down here for years and never had a problem," said David Whitford, a Norwich, Ont., resident currently in Cape San Blas, Fla., who realized he'd technically been driving around illegally for the past few weeks.

"I can't see what the problem is ... for whatever reason they've decided that we're being made to feel a little unwelcome here."

The Florida Department of Highway Safety and Motor Vehicles has said the law was passed so police are not faced with foreign licence documents in languages they can't understand.

An IDP translates existing driver licence information into 10 languages and is valid for one year. It is not a substitute for a valid driver's licence but rather, accompanies one.

In a statement issued Thursday afternoon, however, the department said it learned its new requirement might violate the Geneva Convention on Road Traffic, an international treaty to which the U.S. is a signatory.

"The Florida Highway Patrol will defer enforcement of violations of the amended statutory section until a final determination of the alignment of the amendment with the treaty can be made," the department said.

"Non-resident visitors to Florida who wish to drive while here will be required to have in their immediate possession a valid driver license issued in his or her name from another state or territory of the U.S. or from their country of residence. However, the FHP will not take enforcement action based solely on the lack of an International Driving Permit."

The Canadian Automobile Association -- which issues international driving permits -- called on Florida to amend the law to exempt Canadians.

"No North American jurisdiction has ever asked for an IDP before from another North American jurisdiction. This is a first," CAA spokesman Ian Jack told The Canadian Press.

"They've subsequently told us that they've recognized that it was a mistake to include Canada and that they will be moving to exempt Canada, but on the other hand, because it's legislation and their legislature doesn't sit till mid-March, it's going to take some time for that to happen."

While it has not had reports of Canadians being censured for driving without an IDP in the state to date, the CAA was still suggesting Canuck drivers obtain an international permit until the law is clarified.

Florida's official state tourism marketing corporation has identified Canada as its top international market. Visit Florida said 3.1 million Canadians travelled to the state in 2010.

As word of the change spread on Thursday, many expressed astonishment at the lack of publicity around the new rules. Even the CAA said it only learned of the change when an American Automobile Association worker in Florida called to discuss the new rules two days ago.

"When I first heard I thought maybe it was a joke and then obviously it's not...it's serious," said Christine Ellison, a Georgetown, Ont., resident who often spends her winters in Florida.

"The driving down here is no different than driving in Canada, our licenses are in English, surely they can read them. I don't understand why it would even be necessary."

The IDP costs $25 and can be obtained through CAA offices. Canadians currently in Florida can apply for one through the mail.

The association has been issuing the permits, which are recognized in some 140 countries, since the 1920s.