Judge Clement F. Haynsworth Jr. was told yesterday at a Senate Judiciary Committee hearing that several senators who voted against his nomination to the Supreme Court in 1969 think he should have been confirmed.

"It's a pity you are not on the Supreme Court today," Sen. Strom Thurmond (R.S.C.) said - a view Sen. John L. McClellan (D-Ark.) said he shared. Both voted for Haynsworth's nomination.

"Several senators who voted against you have told me they would vote for you if they had it to do again," Thurmond told Haynsworth, chief judge of the Fourth U.S. Circuit Court of Appeals.

Thurmond didn't name names, but former Senate Democratic leader Mike Mansfield is among those who have said they made a mistake in voting against Haynsworth.

Haynsworth's nominatin was rejected 55 to 45. He was the first of two Southern judges nominated to the Supreme Court by President Nixon who failed to win Senate confirmation. The next year the Senate rejected judge G. Harrold Carswell.

Haynsworth was among the circuit court judges who appeared before the Judiciary Committee yesterday to urge legislation to provide additional judges to handle a mounting workload.

The U.S. Judicial Conference is asking for 107 more district court judges and 25 more circuit court judges, an increase of more than 25 per cent in each category.

Thurmond said that not until this year, when there is a Democratic President to make the appointments, has the Democratic leadership seen fit to do anything about the need for more judges.

The Senate passed a bill last year to create additional judgeships, but it died in the House.However, in 1971 Congress passed legislation creating 61 new district court judgeships.