The District government and lawyers for inmates at Lorton Reformatory asked a federal judge yesterday to approve a $4 million plan to carry out sweeping reforms in security, health and rehabilitation programs at the prison's medium-security facility.

The plan was submitted to Judge June L. Green as a final settlement of a massive class-action lawsuit filed against the city in behalf of the 1,300 inmates in medium security who complained about violence, overcrowding and poor living conditions.

Green said the inmates should be invited to submit their comments on the plan before she gives it final review.

Peter J. Nickles, the lead attorney for the prisoners, called the settlement agreement a landmark among prisoner rights cases that have flooded the federal courts for the past 10 years.

"It is literally a blueprint for improving the medium security facility," said Nickles, who represented the inmates without charge along with other lawyers from the firm of Covington & Burling.

D.C. Corporation Counsel Judith Rodgers said in a prepared statement that the agreement was "workable and fair for all involved" and said the District is committed to meeting standards for safety and rehabilitation of Lorton inmates.

The agreement, among other things, provides that the number of correctional officers be increased from 265 to 331 by 1983 and that the inmate population within the medium security facility be reduced to its approved capacity of 1,166 prisoners by March 1983. In addition, a total of 106 new cells will be constructed.

The city also has agreed to set up a screening center at the D.C. Jail to determine individual needs of new Lorton inmates before they are sent to the reformatory, including housing preferences, reading levels and vocational skills.

It has agreed further to expand and improve various work and training programs designed to eliminate idleness and help prepare inmates for eventual release.