Five members of the National Symphony Orchestra walked the first picket line from 5:30 to 7 p.m. in the orchestra's day-old strike yesterday at the Kennedy Center, after a day in which there were no meetings between orchestra players and management.

The National Symphony String Quartet was scheduled to play a Schubert program at 7 p.m. last night in the Concert Hall with cellist Mstislay Rostropovich, the orchestra's music of the strike, the concert was canceled.

Tuesday night's opening of the 48th season is still in doubt. As of last night, no negotiations had been planned for today.

The orchestra voted unanimously on Friday to strike unless the management came up with an acceptable contract midnight Saturday, the time at which their previous three-year contract expired.

A 3 1/2-hour session at the Federal Mediation and Conciliation Service on Saturday afternoon failed to produce a contract. Musicians Union counsel Philip Sipser said that federal mediator Charles R. Scott and set no time for another meeting, saying that the two sides "were very far apart."

David Lloyd Kreeger, president of the National Symphony Assocation, said yesterday. "Money is the principal issue.I regret very deep that an agreement was not reached in time for the signing of a new contract, I was on the phone for hours last night, following the ending of the negotiating session , and again this morning, trying to work out the problem.

The members of the orchestra, however, say a second issue is very significant. While they voted on Friday 81 to 3 to reject the management offer or $40 a week raise, asking instead for $60, they are greatly concerned about management's demand for a one-year contract.

They cite this statement made by the association last June 26. "Duration: the union has proposed a one-year duration. The association has proposed a three-year duration. In our opinion this is not an area where compromise can or should be made or where the difference can be split. It is imperative that the contract be for a three-year duration. We believe the Union can understand this and agree to it."

William Foster one of the players' representatives in the negotiations, said yesterday, "The National Symphony is not performing because the association engaged in unusual procedures. Three months after they said that a three-year contract was not negotiable, suddenly they shifted without warning to a one-year duration, and there were no meetings of any kind in the interim."

Fosters also said. "The orchestra has already been rehearsing for a week, and it is going wonderfully. The orchestra is excited about its size (there are now 104 players for the first time in NSO history). The board brought Rostropovich to Washington and committed itself to a first-class orchestra, but then they say that they cannot commiehmoselvt tr moes fr ethaeonn commit themselves for more than one year.

"The orchestra will stay out until they have a commitment: Either a longer contract, or a larger kind of money offer than they are making now."

A management spokesman said earlier that symphony directors consider it wise to limit the contract offer to one year, and noted that the symphony faces a serious deficit this year and a larger one next year, even with expenses at current levels.

In spite of the strike vote, small ensembles from the orchestra played during the day at the former home of Nelson Rockefeller on Foxhall Road. The home is this year's Decorators Show House and proceeds from Its use are going to the ochestra. The musicians agreed some time ago to contribute their services to help the orchestra. They kept their promise.

As of yesterday afternoon, orchestra manager Oleg Labanov said that he knew of no initiative in either side for another negotiating session. He also pointed out that the strike endangers the opening of the orchestra's 48th season which is supposed to begin tomorrow night. Final deadline for rehearsals for that concert is 10 a.m. today. If no agreement is reached by then, Labanov said, the program of Schubert and Tchaikovsky slated to be played four times this week, will have to be canceled or postponed.

He also spoke of another decision that must be reached very shortly: the orchestra, under Rostropovich, is engaged to play six concerts in Mexico between Oct. 3 and 8. If the strike continues, a symphony representative will have to call Mexico City to find out the latest date by which a final decision on the Mexican tour can be made.

Meanwhile, in addition to cancellation of the Schubert program, a private concert scheduled for tonight for the World Bank Association has been called off. Rostropovich, eager to begin his second season as National Symphony music director, was making no comment yesterday, but he was telling friends that he was "very, very sad" at the turn of events.

As soon as word of the cancellation of last night's concert was out, the Kennedy Center ticket office began calling ticket holders whose phone numbers were available. Even so, a number of people who did not get the word showed up at the Center expecting to hear Schubert, only to be met with picket signs.

The pickets stayed until 7 p.m. Center attendants stationed at the entrance to parking areas were able to warn in advance many of those who had not gotten word of cancellation of the concert.

Another member of the orchestra yesterday expressed surprise that the board had not offered a satisfactory contract, saying, "This week would have been a very lucrative one for them - sold-out concerts and no soloist, and the World Bank concert for a large fee." She added, "They seemed to think that the Mexico trip would be some kind of attraction for which we would settle quickly."

This is the National Symphony's third strike. In 1969 the orchestra struck for six weeks, not so much over financial problems as what were then regarded as unacceptable working conditons. At the time it was the longest strike in orchestral history. Shortly thereafter, however, the Philadelphia Orchestra entered into a longer and still more bitter strike. Only two weeks ago the Philadelphians signed a new contract at the last minute, avoiding yet another strike.