"Canadian business in many sectors will lose in terms of investment, research and development and jobs because of the BMD (ballistic missile defence) decision," said Jim Westlake, Chairman of the Board of the Canadian Chamber of Commerce.

Many chamber members were dismayed at the decision's impact on information technology, aerospace and defense industry sectors which may have stood to gain from Canadian participation in the scheme.

"It is naive to think that the BMD decision will not somehow have negative economic consequences," said Nancy Hughes Anthony, the chamber's president and chief executive, at a board meeting in Victoria, British Columbia.

Some observers have expressed fears that the United States, which was disappointed by the Canadian decision last month, may now move more slowly to defuse bitter trade disputes over beef and wood exports.

But the proposed missile defence shield, along with Bush, is highly unpopular in Canada, and Prime Minister Paul Martin's decision not to join was seen as the product of his political predicament atop a minority government.