A Virginia Senate investigative subcommittee has agreed informally to recommend that state Sen. Nathan H. Miller (R-Harrisonburg) be rebuked for violating the Senate's conflict-of-interest rule, but likely will say that he broke no law, sources close to the panel said yesterday.

The panel's recommendation, which is expected to be sent to the Senate Privileges and Elections Committee Tuesday, could be as strong as a call for a formal reprimand, or as weak as a statement saying that the subcommittee disapproves of Miller's actions and wants to discourage similar behavior, the sources said.

Either way, such an action would be a first for the Virginia General Assembly, which has never before conducted a formal investigation into conflict allegations against any of its members. Miller, 38, lost the race for lieutenant governor in November after it was reported that he had promoted two pieces of legislation that would benefit his law firm's clients. He could not be reached for comment yesterday.

The same sources who disclosed the subcommittee's intentions about Miller said the investigative panel also has agreed tentatively to recommend absolving Sen. Willard J. Moody (D-Portsmouth), the chairman of the powerful Senate Rules Committee, of allegations that he, too, violated the state's conflict law. Moody, a lawyer, introduced a bill that benefited a legal client and helped kill another measure opposed by other clients.

The subcommittee, however, has not yet reached a consensus on whether Moody broke the Senate's own conflict rule, the sources said. That rule, which both senators have denied breaking, prohibits any member of the chamber from voting on any legislation in which he has "an immediate, private or personal interest."

The state's conflict law, which unlike the Senate rule carries criminal penalties, says that legislators cannot accept money from private sources for performance of their state duties. Both senators have contended that what they did was acceptable for members of a part-time legislature.

The five-member subcommittee, which has been meeting behind closed doors, failed to find any evidence that Miller had intended to mislead the senate through his actions, the sources said. "The general view seems to be that there was no guile involved," said one source. "It was at worst a mistake in judgment, but not a mistake in judgment that the committee wants to condone."

Miller has acknowledged an "apparent conflict" in his dealings with the state's electrical cooperatives, which paid his law firm more than $250,000 while Miller was drafting and voting for legislation that gave them $13.2 million in tax breaks and business advantages. In the final days of his campaign, Miller also conceded promoting another bill that could have helped another of his law firm's clients win potentially lucrative mineral rights.

Some members of the investigative panel had said privately that they were troubled by Miller's acceptance of legal fees while he was providing legislative assistance to his clients. But the subcomittee, meeting in a four-hour closed session Wednesday night in Richmond, agreed informally that Miller's drafting of legislation for clients could not be considered a part of his official Senate duties because drafting legislation is not limited to members of the assembly.

Sen. Howard Anderson (D-Halifax), the chairman of the subcommittee, declined to comment on reports of the panel's deliberations. "I don't know why you can't just wait until Tuesday," he said.

Sources said several subcommittee members concluded that the state's conflict regulations were vague and needed to be overhauled. "If some legislators aren't interpreting these laws the way they should, then maybe the laws weren't drawn so they can be understood," a source said.

It appears unlikely, the sources said, that the panel will make any formal recommendations on revamping the regulations, which are generally considered to be among the weakest in the nation. The panel avoided that question, contending that the issue should be addressed by other committees, the sources said.

Moody, 57, has twice been embroiled in controversies for allegedly using his legislative clout to help his law practice.

In 1977, Moody introduced a bill that in effect overturned a Virginia Supreme Court decision against one of his clients. In 1979, he actively opposed a bill that also was opposed by a railroad workers union whose members bring Moody's firm hundreds of thousands of dollars in business each year.

Moody has rejected the conflict charges as "a bum rap," saying that he realized no specific financial gain from his actions. He declined comment yesterday, saying, "I prefer to wait for the committee's report."