RICHMOND, JAN. 13 -- Gov. Gerald L. Baliles' 1988-90 budget envisions the most significant social services increases for Virginians in at least two decades, including major rises in community services for Virginia's mentally disabled, child care subsidies for more low-income working families and better collection efforts for child support payments.

The spending plan also includes expanded Medicaid coverage for infants and pregnant women, and more nursing home beds for the poor.

"I recognize, of course, that these are significant new expenditures, but there are sound economic reasons for these investments," Baliles said in his State of the Commonwealth address today. "There is also this: It happens to be the right thing to do."

"This is the most substantial emphasis on human resources by any governor in Virginia history as far as I know, certainly in the 16 years I've been here," said state Sen. Joseph V. Gartlan Jr. (D-Fairfax).

Financing for the huge Office of Human Resources would increase by 26.6 percent from the current biennium to $4.8 billion.

As a result, the amount of the state's revenue dedicated to human resources would jump from 19.1 percent in the current biennial budget to 21.2 percent.

Despite the financing increases for the mentally disabled, some advocates and legislators said it still is not enough and that they will push for more from the General Assembly.

Baliles' proposals included:Mentally Disabled. A $65 million increase in funding to the state's 40 community services boards, which are responsible for services to the mentally ill, mentally retarded and substance abusers.

About 19 percent of new financing would go to five Northern Virginia jurisdictions under a state formula.

The initiative's focus would be on residential programs for the mentally disabled who do not need to be institutionalized but who cannot care for themselves.

The amount is slightly less than half of a $140 million, two-year proposal pushed in the last year by mental health advocates and state mental health officials.

The initiative includes $20 million for the first fiscal year and $45 million for the second. The second-year funding, about two-thirds of the level sought by advocates, would become the base for future budgets.

"Frankly, I'm a little disappointed," said state Sen. Edward M. Holland (D-Arlington), adding that he will seek $100 million.

Gartlan, who has said the $140 million is a realistic figure, said he will see if some of the proposed new housing and educational funds can be used for residential programs for the mentally disabled.

Advocates and affected families have claimed that these programs have never been financed adequately in the nearly three decades since deinstitutionalization of the mentally disabled became policy across the country.

Baliles acknowledged in his speech that funding has been insufficient, with Virginia ranking 39th in the country in state support for community care for the mentally ill and 48th for the mentally retarded.

The Virginia Department of Mental Health, Mental Retardation and Substance Abuse had requested an overall increase from the current $752.4 million biennial budget to $1.1 billion.

The governor recommended a two-year total of $958.87 million, a 27 percent rise.

Among the increases would be $9.2 million to add 179 positions at state mental institutions, which have suffered from severe staff shortages, and a salary increase for registered nurses to help draw more to state facilities.

The department budget also includes $5 million for a computerized management information system to track clients.

Another $10.5 million would go to the community service boards for salary increases and inflation costs.

Medicaid. The state's Medicaid costs are expected to jump $145.9 million, a 23 percent increase, just to finance current programs.

This results largely from the projected addition of 4,350 nursing home beds in the state, an 18 percent increase, between now and the end of 1990.

About two-thirds of the patients will be eligible for Medicaid, the health program for low-income people financed jointly by state and federal governments.

Other factors are increased hospital costs and the high cost of treatment for persons suffering from AIDS.

Citing Virginia's high infant mortality rate, 11 deaths per thousand live births, Baliles proposed spending another $16.1 million to expand Medicaid coverage to infants up to age 1 and to pregnant women with incomes at or below the federal poverty level. Currently, Virginia's Medicaid income limit is about 50 percent of the poverty level.

Child Care. Baliles also proposed expanding a child care subsidy program begun by the General Assembly in 1986 from $3 million for two years to $13 million, enough to serve an estimated 3,000 children.

The program, originally intended to help offset declines in federal financing, is aimed at working families who might otherwise be forced to quit jobs and seek public assistance.

Baliles also said he that he is allocating another $1 million for the child care subsidy program for the current fiscal year.

Child care has gained increasing attention nationally as more children live in single-parent households or in families in which both parents work. Baliles' budget noted that Virginia ranks in the bottom third of states in public spending on child care.

Child Support. Trying to reverse the state's poor record of collecting delinquent child support payments, the budget proposes adding $10 million to add 188 new positions to its enforcement staff as an interim measure until total staffing needs are determined.

About $220 million is owed to Virginia's children in unpaid child support, Baliles said.