While President Reagan sings the praises of volunteers and the rest of the administration hums along, there's a discordant note coming from the only federal agency specifically charged with fostering voluntarism.

Action, the agency created in 1971 to mobilize Americans for volunteer service and support self-help efforts of the poor, is trying to unload Volunteers in Service to America (VISTA), the domestic equivalent of the Peace Corps and a cornerstone of Lyndon B. Johnson's War on Poverty.

Critics also charge that the agency, under the direction of Dallas lawyer Thomas Pauken, has swelled its ranks with political operatives while laying off career employes and has diverted the agency from anti-poverty efforts to projects in line with the administration's conservative agenda.

Pauken recently came under fire for threatening to cut off a $1.2 million grant to the nation's largest foster-grandparent project in New York state. The program's directors call the proposed cutoff a vindictive move aimed at them, and say it would jeopardize millions in state funds when the administration is seeking to increase state contributions to social service programs.

Pauken says his agency is entitled to its own initiatives, which include programs for teen-aged volunteers and Vietnam veterans. Pauken repeatedly has vowed to cut off funding to "political or quasi-political groups," and leans toward smaller, less centralized programs that he says will be more likely to be taken over by private sponsors and will involve more unpaid volunteers.

VISTA clearly doesn't fit Pauken's bill. Its volunteers are salaried, at the subsistence level, and have earned the enmity of conservatives for their success in organizing low-income citizens into advocacy groups for social change.

Congress repeatedly has thwarted Pauken's attempts to kill the 18-year-old program, but its funding has fallen from $30 million in the last year of the Carter administration to $11.8 million in the continuing resolution approved last week. The administration's request was for $230,000, just enough to shut the program down.

Despite strong signals of congressional support, VISTA Director Constance Horner told regional directors as recently as October not to approve extensions for volunteers because of "an anticipated phase-out of the program and an as yet uncertain budget for fiscal year 1983."

Pauken said that the agency will comply with the wishes of Congress to train and place 1,800 more VISTA volunteers this fiscal year. But other sources said that the fiscal 1984 budget request again will seek to abolish VISTA.

"It would be a terrible loss," said Ken Allen, executive director of Volunteer, a nonprofit organization promoting voluntarism among corporate and civic groups. "Almost by definition you realize the private sector is not going to pick it up."

Meanwhile, Action announced plans earlier this year to close down more than a dozen of its state offices and lay off nearly 90 more employes (188 lost their jobs last year during a federal "reduction-in-force"), cutting its staff to barely 500.

Language adopted in the continuing resolution forbids closing the state offices, and may also prevent the layoffs. Action officials acknowledged that the proposed layoffs were tied to the closings and the anticipated phase-out of VISTA.

But the targeted employes are not resting easy. After the last round of RIFs, Action found the money to hire more than 80 consultants, experts and other employes outside the civil service.

VISTA's supporters say Pauken has merely substituted his political interests and activists for those of his predecessors, and they point to his choice of regional directors as an illustration of the kind of voluntary efforts he values.

As regional director in New York, Pauken appointed Herbert Stupp, a man who takes credit on his resume for organizing more than 10,000 young volunteers to work for the election of James L. Buckley, the former Conservative Party senator from New York. Stupp worked as a district aide to Buckley, once attending a VISTA conference on Buckley's behalf and "reporting back to him on some of the agency's flaws."

In Dallas, Pauken installed Paulette E. Standefer, who "coordinated volunteers" for Pauken's 1980 congressional race in Texas, and for 10 years recruited and directed volunteers in right-to-life groups in Oklahoma and Texas.

Pauken's choice for regional director in Denver is Naomi L. Bradford, an unsuccessful GOP congressional candidate and a director of the Colorado Conservative Union, who has been active in anti-busing fights since the early 1970s.

Standefer has been criticized halting VISTA funding for several women's projects, including two shelters for battered women. The director of one said she was told Action would not support women's centers because they promoted abortion.

Stupp was behind a recent decision, still under review at Action headquarters, to cut off a $1.2 million grant to the New York Foster Grandparents program, a risky political decision, considering that the program is a great favorite of Nancy Reagan. The agency cited "high administrative costs" in the state program, and said it wanted to spread money around at the local level.

"I don't think anybody should piggyback on the volunteers," Pauken said.

But state officials warn that the move would jeopardize $2.8 million in state funds, much of it in staff support and offices, which they say cannot follow federal grants to the local level.

Action's complaints seem to be directed at the union-negotiated salaries of state employes involved in the program, said Bill Knowlton, a spokesman for the state Office for Mental Retardation and Developmental Disabilities. "They're saying state salaries are too high, which is none of their business," he said.

Knowlton said Action is trying to punish the program's staff for balking at an initial proposal to reduce its funds by 19 percent.

"We kind of irritated them, frankly," he said. "We held a rally and protested the cuts."