Eleven months after Virginia voters approved a package of what state officials described as critically needed building projects, state agencies are locked in a debate over whether two of the projects, training centers for the mentally retarded, should be built.

Their indecision, triggered by opposition from a coalition of health professionals who say Virginia no longer needs such institutions, seems to belie arguments made last year by state officials. At that time officials from then-Gov. Mills E. Godwin to state legislators were assuring voters that all the projects in a $125 million bond issue were essential and could be justified on an individual basis.

Now state mental health officials are saying that was not the case. The two training centers - planned for the Fredericksburg area and the Shenandoah Valley - were placed in the package largely to win support for the bonds in those areas, bond proponents are conceding.

"Obviously it was a political thing," said Preston Carruthers, an Arlington builder who was chairman of Virginians for Bonds, a statewide group that promoted passage of the bond issue. "There was a little bit in there for each geographic area. . .," he said.

In Virginia, a state that has had only two general obligation bond issues since it abandoned pay-as-you-go financing, state agencies were clamoring to get projects included in the November 1977 bond issue. The bond package included funds for prisons, parks, schools, ports and mental health facilities.

At the urging of legislators who argued Virginia has long neglected the needs of the retarded, $1.2 million was included for planning of the two new mental health centers. The centers are campus facilities each capable of caring for more than 200 people, and are like a Northern Virginia training center that the state operates on Braddock Road near Fairfax City.

"Nobody was more surprised then us to see the two centers included in the bond package," said the Rev. Louis H. Fracher, chairman of the state Mental Health and Mental Retardation Board in an interview. Other projects for the retarded had higher priorities but were excluded from the bond issue, he said.

Since the bonds were approved in November, a group of mental health professionals, many from Northern Virginia, have organized and, to the distress of some legislators and local officials, have thwarted plans for the new centers. Their backers include Dr. Leo E. Kirven, state commissioner of mental health, who says his department "is opposed to building any more institutions" for the retarded.

Since 1971 Virginia has cut the number of patients in its institutions for the retarded from about 16,000 to 9,000, Kirven said. Construction of the campus-like training centers on 10-acre sites around the state was Virginia's answer to the national trend away from large, impersonal hospitals that critics said were little more than warehouse filled with retarded people.

The state already has built three such centers, - the one in Fairfax, one in the Norfolk area, and one in the Southwest portion of the state.

But today many mental health professionals are arguing that the centers, planned five years ago by a commission headed by state Sen. Omer Hirst of Fairfax County, do not go far enough toward the state's goal of placing the retarded in a community-like setting close to their homes. The professionals now are urging the state to spend its money on individual group homes that typically would house up to 12 people in communities around the state.

"If the state builds those two institutions, there isn't going to be enough money for more local facilities," said Robert Lorish, a Northern Virginia mental health planner who has led opposition to the centers. "People think institutions are the only way to deal with those different than themselves, when in fact it has been demonstrated that the mentally retarded can grow and learn by living within the community."

State Del. Frank M. Slayton (D-Halifax), a legislator who has long championed the needs of the retarded, said that opponents of the center are wrong if they believe Virginia localities will be able to provide the best facilities. "I can't understand the reasoning of these community people," he said. "It's a fiction to think the local communities can do everything that's needed for the mentally retarded."

Slayton was of the legislators who argued that funds for the centers should be included in the bond package. Former Virginia secretary of human resources, Otis Brown, a member of the Godwin administration's cabinet, agreed the two centers should be placed in a bond package. But not, he says, for political reasons.

"I saw the centers as completing a plan for serving the needs of the mentally retarded in the state," Brown, now a Richmond consultant, said. "The centers seemed like something a citizen could make his mind up on," he said. "They were something you could accept because you could see them. They were not nebulous like air-conditioning for some (hospital) ward," he said, referring to a proposal that had stirred debate in a previous legislative session.

"If I didn't have the full concurrence (of the state department of mental health) in my decision, then I at least had their aquiescence," Brown said.

"Our mistake was that we didn't voice our thoughts loud enough back then," mental health commissioner Kirven said, agreeing with Brown.

"By the time we saw what was on the bond issue, our only choice was to accept or reject the money," said Virginia Lampe of Arlington, former vice chairman of the state's mental health board. "There's no question we needed money for mental retardation facilities; the question is what kind of facilities."

Bonds for the centers have been sold but the money remains unspent. No decision on the fate of the centers will be made until this spring when a consultant's report is expected.