Nearly half the women convicted of violent crimes say they have been sexually or physically assaulted sometime in their lives, the Justice Department reported Friday.

The Department's Bureau of Justice Statistics said that 49.3 percent of violent female criminals surveyed reported such assaults.Among female convicts, violent criminals reported the highest incidence of having suffered physical abuse. Female drug offenders reported the lowest incidence of physical abuse against them - 30.5 percent.

The bureau's study of "Women in Prison" was drawn primarily from its Survey of Inmates in State Correctional Facilities. The survey was conducted in 1986 by the Bureau of the Census and entailed interviews with 3,093 female inmates - or one in six of the nation's female inmates at that time. Interviews also were done with 10,618 male inmates.

The survey found that violent female convicts were more likely to have attacked men - 61.4 percent - than violent male criminals were to have attacked women - 52.7 percent.

Women were more likely than men to have directed violent attacks at victims with whom they had a close relationship. A relative or intimate had been the target of 37 percent of the women convicts but only 17 percent of the male inmates.

Among violent criminals, more than one in four women - 26.3 percent - had killed a family member, ex-spouse or intimate compared to 5.8 percent of men who had killed a relative or intimate.

Almost twice the percentage of male inmates as female inmates attacked strangers - 60 percent to 37 percent.

Among other findings:

-The percentage of female convicts in prison for violent crime dropped to 41 in 1986 from 49 percent in 1979.

-Fraud at 17 percent, larceny or theft at 14.7 percent and drug offenses at 12 percent were the most common non-violent offenses by females.

-More than three-fourths of women in prison were mothers. Two-thirds of the women convicts had children under age 18.

-A third of all female inmates reported they were under the influence of a drug at the time of their offense.

-Two-thirds of the women - 67.8 percent - but four-fifths of the men - 80.3 percent - had prior sentences to prison, jail or probation as an adult or juvenile.