The National Transportation Safety Board, saying that motor vehicle accidents are the leading killer and crippler of children in the country, called on 31 states, including Maryland, and the District of Columbia yesterday to enact laws requiring that small children riding in cars be restrained in safety seats.

Patricia Goldman, vice chairman of the board, said that each year 650 children are killed and more than 5,000 seriously injured or permanently disabled in crashes.

"The most tragic aspect of these losses is that they are needless -- as much as 90 percent of the fatalities and the great majority of the injuries could have been prevented by the proper use of child safety seats," Goldman said.

Nineteen states, including Virginia, have passed laws requiring safety seats for children. The D.C. City Council has given preliminary approval to a mandatory child restraint proposal, with the final vote scheduled for Tuesday.

A coalition of parents, safety officials and legislators has launched an effort to pass a mandatory child safety law in Maryland during the legislative session beginning in mid-January.

As part of its campaign to promote the use of child restraints, the federal safety board is urging people at this holiday season to consider making "a gift of life" by giving a restraint as a gift.

Next month, the board will hold public hearings in Dallas on child passenger safety in Texas, the state with the highest number of child crash fatalities (68 during 1981). That hearing is the first of several planned by the board on the issue.

"We don't have the power to mandate the requirement. We only have the power to raise eyebrows," Goldman said.

In the absence of a single federal standard, states have adopted a potpourri of rules that affect different ages of children and impose different penalties. Some state laws cover only the parents; others cover all adults at the wheel of automobiles containing small children.

After Jan. 1 in Virginia, all children under the age of 4 must be restrained when riding in a motor vehicle registered in the state and owned or operated by the parent. If the child is between the age of 3 and 4, he can be restrained with the car seat belt rather than with a child safety seat.

The penalty for noncompliance will be a $25 fine, with the money earmarked for the state's loaner safety seat program. The fine may be waived due to financial inability or upon proof of acquisition of a safety seat.

The D.C. proposal would require restraints on a child until he reaches his sixth birthday. Until his third birthday, the child must be in a federally approved child restraint seat; after that, a seat belt is acceptable. Anyone driving a D.C.-registered vehicle who did not comply with the law would be subject to a $25 citation by police. The law, if finally approved, will take effect July 1.

A bill was introduced last year in Maryland to require child safety restraints but did not get through the legislature. Plans to promote the passage of child restraint laws during the upcoming session will be discussed today in Annapolis at a seminar sponsored by the Maryland Department of Health and Mental Hygiene and the Maryland Department of Transportation.

During 1981, 633 children under the age of 4 years died in motor vehicle accidents as passengers, according to the safety board. Fifteen of them died in accidents in Maryland and 12 died in Virginia. There were no child fatalities in the District that year.