PORTSMOUTH, N.H. – Tourism officials in New Hampshire and Maine say it’s too soon to tell whether new passport rules will result in fewer visitors.

Starting Tuesday, air travelers who are citizens of Canada, Mexico and Bermuda, as well as U.S. citizens returning home, must with few exceptions display passports to enter the United States. The new rules, mandated by Congress following the terrorist attacks of Sept. 11, 2001, will extend to land and sea travel starting sometime between January 2008 and June 2009.

In New Hampshire, Canadians represent a significant portion of the state’s visitors, and Canada is the state’s top international market. But it’s too early to say how the state will be affected by the new rules, said Victoria Cimino, a spokeswoman for the state Division of Travel and Tourism Development.

David Redekop, principal research analyst for the Conference Board of Canada, estimates that Canadians made 329,000 trips to New Hampshire in 2005, spending $57 million. His agency predicts that due to the passport restrictions, New Hampshire will see 230,000 fewer Canadian visitors and lose $20 million in the next three years.

Maine will see 160,000 fewer Canadian visitors and lose $34.3 million in revenue during that time, he predicted.

Dann Lewis, director of Maine’s Tourism Office in Augusta, said the state has a $6 billion travel and tourism industry overall, and Canadians typically spend between $250 million and $300 million annually there.

He said he’s confident American and Canadian citizens will adapt over time.

“But initially, it will be quite disruptive,” he said.

Linda Pagels, city manager of Calais, Maine, a border town of 3,500 residents, said the rules will pose problems for families who have members living or working in both Maine and Canada.

She also questions whether a Canadian or American family of four would pay hundreds of dollars to provide each of its members with passports.

With Maine and New Brunswick planning to build a new bridge to ease border traffic and the Canadian dollar at its strongest since the 1970s, Calais retailers were looking forward to strong sales, she said.

“Just when we think our economy is going to get a boost, we get a kick in the teeth,” Pagels said.