Ronald Reagan talked over foreign policy and Senate confirmation problems here yesterday with his future secretary of state, Alexander M. Haig Jr., amid increasing signs that Haig will face little serious opposition when hearings begin Friday on his nomination.

If some Democrats still want to raise serious questions about Haig's suitability for the nation's top diplomatic post, they appear now to lack two things -- time and documentation. There are also growing numbers of Democrats who are saying publicly that Haig's role in the Watergate era of Richard Nixon should not be a chief concern at the hearings.

At the same time, Haig, with the backstage help of key advisers, lawyer Joseph A. Califano Jr. and Reagan Capitol Hill specialist Tom C. Korologos, is conducting what appears to be a successful courtship of the Senate leadership and Foreign Relations Committee membership, including a private meeting with his most severe critic, Senate Minority Leader Robert C. Byrd (D-W.Va.).

Emerging from a 90-minute morning meeting with President-elect Reagan at Blair House, Haig, under questioning by reporters, indicated no objection to a possible Senate committee review of documents and tape recordings from his days in the Nixon White House. But Haig said "I would hope there would be a degree of reason" from the Senate panel in exploring such matters in relation to current foreign policy problems noting that "millions of taxpayer's dollars" had already been spent gathering "reams of testimony," including his own, about the Nixon era.

Haig said yesterday he did not anticipte any problems at the hearings, and there were few lawmakers on either side of the aisle who were disputing that.

Although the leader of the minority on the Foreign Relations Committee, Sen. Claiborne Pell (D-R.I), has asked the White House and other government agencies to release Watergate-era tape recordings and other materials, sources close to Pell acknowledged last night that "it doesn't look too good" in terms of the chances for such release.

Access to those records Pell has requested of the Carter White House will probably be blocked by normal bureaucratic delays, says Fred Thompson, the special counsel for the Republican majority of the Senate confirmation panel.

A far more serious blow came yesterday, however, when former president Nixon's lawyer, Herbert L. Miller, threatened court action to keep Senate Democrats from gaining access to the Nixon White House tapes or other documents relating to Haig. The Democrats have asked for material relating to Haig's role in the former president's Watergate defense, in the eventual pardon of Nixon by President Ford, in wiretapping of officials and reporters during the Nixon years, and in foreign policy advice on issues such as the bombing of Cambodia.

Miller, according to news service accounts, claimed that the Presidential Recordings and Materials Preservation Act, passed by Congress during the Watergate trials, does not allow material to be made public at the request of one senator. Rather, he argued, if Congress wants something, the normal way to get it is with a subpoena.

The Foreign Relations Committee chairman, Sen. Charles Percy (R-Ill.), has said, according to his aides, that he has no objection to the Democratic quest for material nor would he block it. But Thompson and other committee sources indicated yesterday that it would be highly unlikely that the Republican-run committee would issue subpoenas to gather information that could complicate and eventually lengthen Haig's confirmation process because the subpoenas would result in extended litigation.

Percy has repeatedly stressed that he wants Haig to be confirmed by the Jan. 20 inauguration date so the nation will have a secretary of state in place at a time of serious international problems.

The hearings will open Friday, will include a Saturday session and will resume early next week. Though the hearings could run for several additional days, some Senate sources thought they would end sometime next week and that Haig, while available for as long as the hearings continue, will probably be the main witness only for the first three days.

Percy, as chairman, and Pell, as ranking minority member, will both make opening statements. Haig is preparing a major and lengthy statement addressing all of the foreign policy issues confronting the new administration which will constitute his opening statement and which is apt to focus attention, at least at the outset, on foreign policy and Haig's suitability for handling it rather than on other matters.

The committee staff has prepared two thick briefing books for the 17 members. One involves the key foreign policy issues as the committee sees them and the other is a collection of articles, documents and other materials that relate to Haig's government service.

Haig, according to transition team sources, has either visited or made arrangements to see all of the committee members thus far except four of his potentially toughest questioners -- Democratic Sens. Alan Cranston of California, Paul E. Tsongas of Massachusetts, Paul S. Sarbanes of Maryland and Joseph R. Biden of Delaware.

Yesterday, Haig visited with the committee's most junior Democrat, Christopher Dodd of Connecticut, who told reporters afterward that he has "never been a Watergate junkie" and that he intends to question Haig on international problems.

Biden had told reporters earlier that "the only issue that doesn't concern me is Watergate." The big issue, Biden said, is the strategic nuclear arms talks with Moscow. Sen. John Glenn (D-Ohio), another committee member, has also said he doesn't believe Watergate should be a main concern at the hearings.

Sources close to Haig say that the retired four-star general has gotten used to the criticism that has been leveled at him from some quarters but that the attack that stung and dismayed him the most was the one launched publicly by Byrd at a news conference on Dec. 6. Though not a committee member, Byrd, as Democratic leader, is a powerful figure and Haig viewed the senator's criticism as an attack on his integrity.

On Monday, after a meeting with Haig that was not publicly announced, Byrd issued a statement saying that "if there are not any particular problems" in the Haig confirmation hearings, "our role will be to expedite the confirmation process."

Democratic sources say Byrd, who now heads a minority rather than a majority and faces a significant change in his impact, is under considerable strain in adjusting to his new role, and that while he still harbors misgivings about Haig he is not sure which way to go.

Sources close to Haig described the meeting with Byrd as going "pretty well" and was carried out "without vitriol or bitterness." The impression gained from Byrd, these sources say, was that the questioning would be carried out in a serious, balanced way without an attempt to politicize the event. These sources believe the two men parted with mutual respect.

At the moment, neither side has formally requested any other witnesses at the hearings. Sen. Lowell P. Weicker (R-Conn.), however, reportedly has told Haig and Republican Leader Howard H. Baker Jr. of Tennessee that he would ask to testify against Haig, according to Reagan transition sources. As a junior member of the 1973-74 Senate Watergate Committee, Weicker presided at the closed-door session where Haig first claimed executive privilege in refusing to tell what he knew about Nixon's involvement with his friend and benefactor, Charles G. (Bebe) Rebozo.

If Haig's upcoming testimony is not sufficient to put to rest any qualms about his integrity, Republican counsel Thompson said former Watergate special prosecutor Leon Jaworski may be called in Haig's behalf.