The State Department yesterday welcomed "as a long overdue decision" reports that more than a dozen Jewish dissidents will be allowed to leave the Soviet Union.

Department spokesman Charles E. Redman noted, however, that it seems to be the sort of "high-profile public gesture" often made by the Soviets before a meeting such as the one scheduled here next week between Secretary of State George P. Shultz and Soviet Foreign Minister Eduard Shevardnadze.

Redman, commenting on reports that prominent Jewish activists Josef Begun, Vladimir Slepak and others will be permitted to emigrate, said: "These people have struggled long and hard for their right to leave the Soviet Union."

He added that the United States remains "deeply concerned" about other long-term Jewish applicants denied permission to leave and "disappointing" progress in permitting dual nationals or Soviet spouses of Americans to come here.

Redman noted that Jewish emigration from the Soviet Union has been averaging about 800 people per month since April, compared with 916 for all of last year. "But it's far less than the 2,000 per month during the 1970s" at the height of detente, he said.

Shultz, in an interview with The Associated Press, said the United States is discussing with Moscow an overhaul of Soviet emigration procedures to see whether the process can be made "less arbitrary, work better, be more humane and more understandable."