The Judicial Conference of the United States asked Congress Thursday to create 73 new judgeships to cope with the still growing caseload in the federal courts.

The action came at the biannual meeting of the conference, the policymaking body of the federal judiciary.Fifty-one of the 73 judgeships would be permanent under the conference proposal, while 22 would be five-year temporary positions to handle backlogs in various courts around the country, explained David Sellers, spokesman for the Administrative Office of the U.S. Courts.

The proposal, if enacted, would increase the number of federal district judges from 548 to 607 and appellate judges from 158 to 172.

Sellers said more judges are needed partly because of the still growing caseload facing district courts and courts of appeal and partly "because there are a number of proposals pending before Congress that would give us additional workload."

The last increase in the judicial work force was in 1984 when Congress authorized 86 new judgeships.

In early 1987, the Judicial Conference asked for 80 more judges, but Congress failed to act on the proposal, largely because of Democratic fears that a further expansion of the judiciary would give President Reagan too much influence over the courts.

Since he took office in 1981, Reagan has named 49.6 percent of the federal bench, including 289 federal district judges and 81 appellate judges.