BERLIN  Microsoft and the European Commission have canceled the only hearing planned in an antitrust investigation into the company’s Internet browser because of a dispute over the attendance of European regulators serving as advisers.

As a result, the commission, which began its inquiry after a complaint by Opera, a small browser maker in Norway, will reach its decision and levy a fine based on written statements from Microsoft and its adversaries. Microsoft decided not to give oral evidence in the case after it was unable to persuade the commission to move the meeting, scheduled for June 3 through 5, so that it did not conflict with a global antitrust conference in Zurich that draws European antitrust regulators.

Dave Heiner, a Microsoft vice president and deputy general counsel, said the conflict would have prevented some regulators from attending the hearings as observers and advisers.

“It appears many of the most influential commission and national competition officials with the greatest interest in our case will be in Zurich and so unable to attend our hearing,” Mr. Heiner wrote on his blog on the Microsoft Web site.