Three years ago, when Congress ordered that regional "health systems agencies" be set up across the nation, it pitted health care professionals against "outsiders" in the fight to control rapidly rising health costs.

The health agencies, which include laymen on thier boards, have bumped repeatedly into local governments over abortion, smoking and other issues and have irked some doctors and hospital administrators who have believed themselves snubbed on long-range health planning decisions.

And while some say this troubled relationship may be improving, it remains - as yesterday's action by the Fairfax County Board of Supervisors shows - a prickly one.

"What has really happened in Northern Virginia is that prior to the last December the HASA had alienated practically every group of providers here," said Frank Iams, director of the Fairfax County Hospital Association. "If the providers are autagonized and thus openly opposed to the efforts of the HASA, then those efforts are going to be slowed down and perhaps doomed to failure."

Indeed, doctors in Virginia were unhappy enough to assess each member of the Virginia Medical Society $50 to set up the "Vanguard Committee" to monitor actions by the HSAs in Virginia.

"Some of our critics traditionally have made the decisions about the health care delivery system," said Laura McDowall, chairman of the 30-member board of the Noryhern Virginia HSA. "All of a sudden there was a new kid on that block. It was ween a new threat. That's pretty basic."

The Northern Virginia agancy is widely considered to be the most agressive of five such regional planning bodies that cover Virginia. It is the first in the Washington area to receiv full accreditation by the Department of Health, Education and Welfare.

The HSA reviews all proposals for new or expanded health facilities and equipment costing $150,000 or more. It also has developed a 1,000-page, five-year plan for health care and an annual implementation plan that led directly to the action yesterday by Fairfax County.

The Northern Virginia HSA plan, in a section dealing with equal access to health care, calls for removal of "financial barriers for abortions for Medical-eligible women in Virginia."

HSA officials view their stand as an attempt to provide equal medical treatment for ll and the transmission of information and reports to the Virginia General Assembly as a proper action for a pulicly financed planning body.

But antiabortion groups call it "lobbying" for abortion and have mounted a campaign with local governments to cut off funding.

HSA officials view the withdrawal of local funding - about 6 percent of their $635,000 budget - over issues claim the actions result largly from a lack of understanding of the agency's role.

A more important problem is the HSA's relations with the professional health care community.

"Let's face it," said Dr. C. Barrie Cook of Fairfax City, a member of the HSA board, "Any time you are talking about somebody else, the ones they are trying to control are not very happy about it."

Dr. Richard L. Fields, a former board member, president of the Fairfax County Medical Society and chairman of Vanguard, said, "This may be the most significant health care legislation ever - even more than Medicare/Medicaid. I think we recognize that the law is not going to be repealed. It is here to stay."

McDowall, wife of a pediatrician, and Dean Montgomery, the HSA executive director, said the hostility from health providers seemed to have peaked in December and that the present relationship is improved, if still shaky.

"Dr. Fields has some philosophical differences with the law. I don't think we will agree on everything, but I think they recognize that," Montgomery said.

"If we stand off at 10 paces and spout philosophy at each other we will never get anything done," Montgomery said. But as doctors, administrators and planners work together on complex, highly technical health problems, the "commonality of views may be closer than people realize," said Montgomery, who heads a staff of 18.

The HSA has for two years been reviewing "certificates of need" that must be approved by the Virginia state commissioner of health before facilities can be built or expanded.

The actions often embroiled the HSA in sharp conflict with individual hospitals on specific issues. But the HSA - and the major role it was assuming - remained largely unrecognized until last December.

In that month, the HSA presented a draft five-year plan for public hearing - and was met with an outraged roar from the health community, which felt it had been consulted during the plan's development.

Cook, a pathologist, agrees that health experts should have been consulted more. "I think the HSA did everything legally that it was required to do but I'm not sure how much efforts they made beyond that."

"Most of the doctors in the community don't know much about the HSA and they did not get concerned during the meetings last spring and summer. It was only when the plan came out that they realize how important it was," Cook said.

Both friends and foes of the HSA argue that much of the opposition to the draft plan was emotional - a sudden realization that power had shifted.

"The reaction surprised us. We were reeling from the hostility," McDowall said of the public hearings. The board then spent hours going back through each item in its plan in an effort to answer specific criticisms, she said.

The plan covers traditional areas such as numbers of hospital beds and heart surgery facilities, and "social" concerns such as smoking, traffic safety, air quality and sex education. It urges actions by local, state and federal governments.

"The plan is like a bible of medical theology. You could not possibly disagree with it," said Dr. Helen Hackman, who recently resigned as Arlington County human resources director.

"The concern is that this whole thing is laying the groundwork for a national health service . . . It has the potential for being devasting," Hackman said.

McDowall defended the range of the plan, saying the HSA is fully aware that it does not have power to enforce speed limits or stop smoking but that those things do have major impact on health.

Another major attack on the HSA takes aim at the composition of the board, which has 23 members appointed by local governing bodies and seven chosen by the Northern VIRGINIA Planning District Commission.

The federal legislation, aiming at preventing the packing of the boards by a local health care establishment, decreed that at least half the member must be "consumers." It also defined "providers" as including wives of health care professionals and others closely linked to professionals.

"If you were going to build an airliner, yoou would hire an aeronautiacal engineer and not a passenger," Fields said.

McDowall argued that the board seldom splits on consumer-provider lines and that professionals in health fields will be heavily involved in task forces and study groups working on specific problems.

Fields said his "best prognosis" is that "all concerned will meet somewhat in the middle. I hope our elected officials will be made aware of defects and I hope the HSA boards will let the providers give advice. And the providers are going to have to accept some of the restrictions placed on us by law.

"Unless that happens, the HSA's will not be effective, the provider community will become more hostile, the consumer will become less interested and the law may be repeated," Fields said.