A new ruling will limit the extensions to 15cm, which is half the length of the bars Obree used to regain the world 4,000 metres pursuit title last year.
"We want riders to win because they are the best, rather than because they have the best equipment," the UCI president, Hein Verbruggen, said.
"As far as I am concerned they are not putting riders' interests first," Obree said. "If I am going to get hassled what is the point in racing." He has already hinted that he might retire to concentrate on marketing adjustable versions of his handlebars.
Obree devised the style which has the arms outstretched ahead of the rider, and, in his case, his hands level with the front of his wheel. Chris Boardman used it to take the world 4,000 metres title and then the world hour record.
Today Obree is chasing his second world title of the year against a strong local challenge from Alex Zulle and Tony Rominger.
Britain's best display on the opening day of the world road championships was a good sign for Boardman. Paul Manning, who partnered the world champion to a recent victory, finished 10th in the Under-23 time trial, 2min 39sec off the winning pace of Italy's Luca Sironi.
Yvonne McGregor was 16th in the women's 26.4km time trial, 2:45 slower than the French winner, Jeannie Longo, who, at 38, took her 11th world gold.
Results, Digest, page 31