The long-running battle over the right of cafeteria workers to unionize at the House of Representatives took another turn yesterday when congressional officials conducted an "informal poll" on the issue but were immediately accused of rigging the ballot.

Employes of Congress, who in some cases have complained about low pay, poor working conditions and lack of grievance procedures, are among the few workers in the nation who do not have the right to organize unions because Congress exempted itself from labor laws.

Yesterday's vote -- which was boycotted by a majority of the 235 House cafeteria employes, according to union supporters -- follows conflicting claims about whether the employes want a union and should be allowed to have one.

The poll, conducted by George White, the architect of the Capitol, who supervises food service, resulted in 68 votes against a union, 31 in favor and 13 no-opinions, according to William Raines, assistant to the architect. But 52 percent of the eligible voters did not vote.

"We anticipated criticisms of the poll. But we think this is a good indicator of opinion," Raines said. He said the results will be reported to the House Administration Committee, which oversees the services.

But supporters of the union effort said the polling was unfair because the questions were biased, nearly 40 supervisors were allowed to vote, and threats were made that a prounion vote could result in the hiring of a private contractor to run the Capitol's 10 dining facilities.

"If ever there was a rigged ballot, this is it. This was a mockery of due process," said Fred Feinstein, counsel to the House subcommittee on labor-management relations.

The poll was biased, Feinstein said, partly because the union question followed four other questions that asked employes whether they were satisfied with various improvements in working conditions that White had made since taking over food service last January.

Rep. William L. Clay (D-Mo.), the subcommittee chairman, said White showed "callous disregard for fundamental fairness" by including questions about management performance on the same poll questioning union preference.

Roughly 75 percent of the cafeteria workers have signed union-authorization cards seeking representation by the International Association of Machinists, an AFL-CIO industrial union that also represents government employes, according to IAM, which plans to picket the Capitol next month over the issue.

Raines said that contrary to IAM claims, House officials have received petitions from a majority of workers saying they do not want a union.

Cafeteria workers earn between $4.64 and $10.76 per hour and, until White changed procedures this year, were not eligible for overtime and were frequently laid off.