Hundreds of government officials -- scientists, educators and researchers -- may resign this spring to avoid coming under a stringent new code of ethics aimed at curbing conflicts of interest.

The 1978 Ethics in Government Act requires detailed financial disclosure statements and puts stiff limits on what high-ranking officials may do in the private sector after they leave government.

Several affected officials say the limits in the law may leave them virtually unemployable outside the government after the act takes effect on July 1.

"Under this law, I couldn't go back and do most of the things I have spent a good part of my life doing." said Hale Champion, undersecretary of health, education and welfare. "I have to consider resigning if the implications are as grave as they look."

Others who said they could be similarly affected include Richard Atkinson, director of the National Science Foundation; William J. Perry. director of research and engineering in the Department of Defense, and Donald S. Fredrickson, director of the National Institutes of Health.

They are typicalof hundreds of executives, professors, scientists and others who join government for a few years, intending to return eventually to their old jobs or to others like them. Often these jobs are at nonprofit or academic institutions having extensive government research grants; others are at private companies withlarge federal contracts.

"The higher up in the decision-making you are, the more difficult it becomes," said Champion, who was formerly vice president for finance at Harvard University. "You then have official responsibility for lots of things you don't deal with personally... it could come down to meaning you can't participate in the governance of any institution that has anything to do with the government."

The new law covers all federal employes at grade GS16 or above or earning more than $42,500, which includes nearly everyone in a policy-making position. It alwo covers judges, members of Congress and senior congressional staff members, as well as political appointees: in all, about 15,000 persons.

Passed in the wake of the Korean influence-buying scandal, the measure requires listing outside income, gifts, debts, property transfers, spouse's income and holdings and other financial matters beginning May 15.

It also tightens existing lifetime bans on representing outsiders before the government on issues in which the official had "personal and substantial" dealings while in government. And it extends from one year to two the ban on acting for a private party in issues that were under the policymaker's "official responsibility" in the year before leaving public office.

These provisions, effective July 1, are not considered particularly troule-some to scientists and academics, although Atkinson criticized the requirement that even those who serve on advisory boards for as little as 20 days annually must file disclosure statements.

Far more troubling, according to those concerned, is the provision that says a former government official shall not "aid, assist, counsel, advise or assist in representing" before the government a private organization on any matter under the official's former jurisdiction. "He can't talk about anything he knows anything about," summed up an HEW official.

This could mean, said Fredrickson of NIH, "that quite prossible I would be barred from my old job" as president of the National Academy of Sciences Institute of Medicine. It involved handling government contracts and studies which concerned NIH, he said.

Another 20 persons now at NIH -- "the people who run the institute, the key administrators" -- would be affected, he said. "The law might mean that our usual movement from medical schools and the academic world and back would be severely impaired."

Perry of the Defense Department was formerly president of an electronics firm in Sunnyvale Calif. "I don't believe I could return to that job under this as I read it," he said, "an I would certainly like to have that option."

Perry added that many DOD engineers who oversee research and acquisition programs have told him they are considering resigning before July 1. "We may so completely limit the ability of a technical manager to return to industry that we may not be able ot hire them away from industry in the future," he said.

At the National Science Foundation, Atkinson said that under the provisions of the law as outlined by a reporter, "I would probably never have come here in the first place" since he would probably be unable to return to Stanford University. where he is on a leave of absence. "If that is the case. I would think twice about whether I'd have to resign" from NSF, he said.

HEW Secretary Joseph A. Califano Jr. said that he and Defense Secretary Harold Brown had "expressed serious concern" about the matter to President Carter. "We suggested that the thing to do is to postpone the effective date of the law and have some hearings on it," Califano said. "We would hope the law could be aemended."

Carter, he said, had asked aide Jack Watson to look into the matter.

Jim Graham, staff counsel to the Senate Governmental Affairs Committee that drafted the new law, said there is "a severe lack of information" among those affected. "We do think the bill is reasonable. One of the ways scientists make a living is through consulting and there is at least the same potential for abuse as there is with lawyers," he said.

He and others suggested that an exception in the law permitting "scientific and technical communications" with the government might be adapted in forthcoming regulations to solve some of the problem, although new legislation might also be necessary.

At the moment. all eyes are on Bernard Wruble, 36, who is drafting those regulations in his first week on the job at the brand new Office of Government Ethics. The post was established by the act within the Office of Personnel Management (the old Civil Service Commission) to come up with rules on application and enforcement of Ethics in Government.

"We are aware of the scientists' problem," he said. "We feel we have an obligation to settle the problem well in advance of the time when people will have to act on it."