Mayor Marion Barry's summer employment program for youth was dealt a setback yesterday on Capitol Hill when Congress delayed further action until July 10 on a budget that would provide money for 8,564 jobs.

The congressional move surprised and distressed city officials, who had hoped to have 30,000 youngsters at work by July 9 at the latest, including the 8,564 who would be paid out of the funds sought from Congress.

It was not clear last night how long after July 10 it might take to put the youths to work if Congress agrees to provide the money.

Until the delay to July 10 was announced yesterday, the next step in the budget process has been scheduled for today, with an expectation that the money might be voted before Congress leaves later this week for a July 4 recess. The lawmakers are scheduled to reassemble July 9.

"I'm disappointed, but it's too early to say what it means," the mayor's special assistant for youth affairs, Audrey Rowe, said after learning of the congressional delay.

Rowe convened an urgent meeting of city officials, including Matthew F. Shannon, acting director of the D.C. Department of Labor, along with budget and youth affairs experts. She said they "tried to figure out what kind of signals to send out to the youngsters" about job prospects, and reached no agreement on recommendations to the mayor.

Kwame Holman, Barry's assistant press secretary, said that mayor had no comment.

The delay in Congress was procedural, and not directed at the District of Columbia.

The money to finance the jobs program $7.3 million, is only part of a $53.1 million supplemental budget for D.C. The city funds, in turn, are a small part of an appropriation bill to provide supplementary funds for most of the agencies in the federal government.

Conferees from the House and Senate had been expected to meet today to iron out the differences between versions of the bill approved by the two chambers. If agreement had been reached, the chambers could have taken final action later this week.

Because of the press of congressional business, aides said, the meeting of the conferees was put off to July 10.

Agreement by the conferees is crucial to the mayor's jobs program, since the $7.3 million in needed funds are included in the Senate's version of the bill, but not in the House's.

Rep. Charles Wilson (D-Texas), chairman of the House subcommittee that deals with the D.C. budget, has announced his support for the outlay to pay for the 8,564 jobs.

Funds for the other 21,400 jobs already have been allocated to the city, some under federal programs and some to be paid by nongovernmental sources.

Barry, who promised during his election campaign to double from 15,000 to 30,000 the number of summer jobs for chronically unemployed city youth, made the employment package a top priority item.

He has described youth unemployment as a crisis. According to a report being prepared by the D.C. Department of Labor, unemployment among local youth aged 16 to 19 years doubled - from 17.7 percent to 38.9 per cent - between 1970 and 1978.

Unofficially, some city officials said thay did not need final congressional action on the jobs budget before moving ahead on the program - but they required a clear signal of the lawmakers' intentions.

Shannon, the city labor director, said last week that some hiring of youth had to be delayed beyond the original target date of tomorrow because the city had been unable to do all the paperwork that was needed. If all the funds had been available, he said, all the youngsters would have been at work by July 9.

Gladys Mack, the city's budget director, said it was too early to assess the impact of the delay on the jobs program and other city operations.