John Bromley, European director of the Construction Confederation, met commission representatives in Brussels this week to discuss the concerns of UK contractors.
Under the commission's proposed Consolidated Procurement Directive, the preferred bidder stage of tendering would be removed and a process of "competitive dialogue" introduced at any time up to the final contract award.
Bromley said the directive would limit competition and increase bidding costs for contractors, who would be forced to compete for longer before finding out whether they had won a job. "The likely outcome is that contractors would not be able to afford to compete for as many projects and would instead concentrate their efforts on specific projects, which would reduce competition," he said.
The proposed move is high on the commission's list of priorities and, if agreed, would come into force by 2003.
At present the initial stage of bidding is followed by the shortlisting of three or four contractors, who then submit more detailed tenders. A single preferred bidder is selected on the basis of these tenders.
The preferred bidder then enters exclusive negotiations with the employer to finalise elements of the contract such as design structure and costs.
However, the European Commission is concerned about lack of competition in the procurement system and whether it is sufficiently open to public inspection.
Bromley's trip to Belgium follows a meeting between the confederation, MEPs and European Union officials in Brussels at the beginning of the month.
This was led by Bill Rabbetts, chairman of the National Federation of Builders.
Rabbetts said the key concern with the draft directive is that it could severely restrict dialogue between clients and contractors during the final stages of negotiations.
He said of the meeting: "We were successful in putting our views across and had very positive feedback from the MEPs present, who backed our views and promised to support our amendments."