Six Physically handicapped children have been unnecessarily and illegally kept at the Hospital for Sick Children, some of them for longer than two years, by the D.C. Department of Human Resources, lawsuit filed in D.C. Superior Court charges.

The children, all declared neglected and placed in DHR custody by the Family Division of Superior Court, have been denied the right to mental, emotional and physical development that both city and federal laws guarantee them, the suit contends.

Attorneys Wallace J. Mlyniec of the Georgetown University Law Center's Juvenile Justice Clinic and Jean Bower, director of the Volunteer Attorney's Office, asked that the court order DHR to place the children, who range in age from 6 to 15, in suitable foster care:

The children may have needed hospitalization initially, but they are now being denied the "home-like atmosphere" they need and are entitled to, the suit charges.

Lawyers said the hospital has told DHR the children are ready for release, but, but, DHR fails to remove them. The hospital's rates are far more costly than maintaining a child in foster care, attorney Bower said.

DHR pays approximately $2,200 a year per child under 12 in foster care and about $2,400 for those older. Dale Lowe, administrator for those older. Dale Lowe, administrator of the Hospital for Sick Children, said his facility charges about $90 a day per child - or about $32,850 a year.

Reached for comment on the lawsuit, William W. Barr, DHR social rehabilitation administrator, said the children are "really sick and difficult to place anywhere." If they were not in the Hospital for Sick Children, he said, they would have to be in another similar facility.

Barr said he had no knowledge of the lawsuit. He noted that the children are medically eligible for the federally funded Medicaid program, which pays for their care at the hospital, an indication of their serious condition.

Among the six children are three 6-year-old mentally retarded boys, one with celebral palsy as well. One has been hospitalized for 3 1/2 years and was ready for release more than two years ago. The second, placed in March, 1975 was eligible for release in January, 1976. The third, placed in Spetember, 1973, was ready for release two years ago. The other children include:

A boy, 6, whose burn-scarred skin requires daily treatment. Hospitalized for 18 months, he was placed in a foster home for three days last February.

A girl, 11, made a quadriplegic by but the parents, whom DHR inadequately informed of his condition, refused to keep him, the suit alleges. a car accident, hospitalized for three years, and ready for discharge for 18 months.

A 15-year-old boy who suffers seizures. He was placed in July 1974, and declared ready for release a year and a half ago.

In addition to Barr, the lawsuit names as defendants Mayor Walter E. Washington, acting DHR director Albert P. Russo and Betty McQueen, chief of the agency's family services bureau.

Attorney Bower said the six children are among a larger group maintained at the hospital by DHR, but were named in the suit because "they were medically cleared for foster care quitea while ago."