Republican John W. Warner has edged slightly ahead of Democrat Andrew P. Miller in an exceedingly close race for the U.S. Senate in Virginia, according to a poll published today by the Richmond Times-Dispatch.

Disclosure of the newspaper's second poll in the race came as new financial reports were released showing that Warner, making his first bid for elective office, is outspending Miller, a former state attorney general, by more than a 2-to-1 margin.

The newspaper's poll showed that Miller's support has eroded since a September poll in which Miller had a six percentage point lead.

In the latest poll, taken after Miller began his intensive attacks on Warner's credibility, Warner, now leads Miller by a 32-to-30 percent margin. Almost 4 out of every 10 voters the newspaper interviewed said they still are undecided or declined to answer questeions about the Senate race.

In the newspaper's earlier poll, a similar percentage of voters was listed as undecided. Miller then was leading Warner by 34 to 28 pecent.

Voters' attitudes toward Warner's wife, actress Elizabeth Taylor, took a turn toward the negative in the poll. In the latest survey, 40 percent said she will not help Warner's chances of winning and 37 percent said she will. The remaining 23 percent were undecided or declined to answer.

In the first survey, 41 percent of those questioned thought she would help and only 34 thought she would not. One out of four voters were undecided then or did not answer the question.

The results of the newspaper's survey buttress a growing perception that the Miller-Warner contest is extremely tight as the candidates enter the final 10 days of campaigning.

A private partisan survey, compiled four days after the Times-Dispatch poll was completed, and made available to The Post, shows Warner and Miller running dead even among all voters and Warner slightly ahead among those most likely to vote.

The Times-Dispatch poll also found that voters surveyed favor a ballot proposal for legalization of betting at horse races in Virginia, but by a substantially smaller margin than they did in the first poll. In the most recent survey, 48 percent favor parimutuel betting while 39 percent oppose it. In the September poll, horse track betting was favored 54 percent to 33 percent.

In both surveys, 13 percent were undecided or declined to answer the betting question.

The Times-Dispatch telephone survey of 683 registered voters selected at random was completed on Oct. 22, 16 days before the Nov. 7 election and one month after the first survey.

John B. Mauro, director of research for Media General, Inc., corporate parent of the Richmond newspaper, said he interprets the latest poll to mean the Senate race is a "virtual standoff." He noted that Warner's lead falls within the 4 percent margin of error probable in such a random sampling of voters.

The Warner gain, however, apparently indicates that he did not suffer much from early campaign gaffes that were widely reported, and criticized by Miller, between the two surveys.

Since the second poll was completed, newspapers have disclosed that Warner contributed to the presidential campaigns of former president Richard M. Nixon in 1968 and 1972 although he had told reporters and editors of The Washington Post in an earlier interview that he had not.

Miller has made an issue of these statements and questioned whether contributions to Nixon by Warner and his former in-laws in the wealthy Mellon family influenced his appointments as undersecretary and secretary of the Navy.

Warner, former husband of Catherine Mellon, is himself a million-general election compared to $387,000 aire and now has a personal financial stake of $812,000 in the Senate race. According to newly released financial reports, he has spent $814,000 in the general election compared to $397,000 for Miller.

Warner, has financed his general election race with loans totaling $321,000 and paid off loans amounting to $491,000 for his preconvention race for the Republican nomination. He lost the nomination to conservative Richard D. Obenshain in a close race, but was named the party's nominee after Obenshain died Aug. 2 in an airplane crash.

The latest Times-Dispatch poll was completed before the start of most of the radio and television advertising planned by the two candidates. Warner is expected to spend at least $200,000 for his media campaign, perhaps twice as much as Miller.

Miller has criticized the size of Warner's personal loans to his campaigns and the expected intensity of the Republican's broadcast advertising, which Miller has labeled a "media blitz."

Warner's loans account for most of the campaign spending lead he has over Miller, but the Republican also has managed to raise more in contributions, especially from relatively small givers, than has the Democrat.

Since he won the Democratic nomination on June 10, Miller has raised $442,000 in contributions from individuals and political action committees. Less than one-fourth of this amount has come from contributors of less than $100.

Since his nomination on Aug. 12, Warner has raised $456,000 in contributions and his total of $209,000 from contributors of less than $100 is more than double Miller's small gift total of about $100,000.

The Warner campaign reported 12,751 individual contributions. The Miller campaign did not have a count of individual gifts.