Between 10 and 15 past or present employes of Metro accepted meals, golf greens fees and other gifts from construction contractors and may have violated federal conflict-of-interest laws, the U.S. Department of Transportation's inspector general said yesterday.

Joseph P. Welsch said that an ongoing investigation by his office will attempt to determine whether the alleged gift-taking in 1977 and 1978 affected decision-making at Metro. Findings on these and other potentially illegal acts that he declined to describe are being referred to the Justice Department, he said.

Disclosure of the gift-taking came out of a four-month study by Welsch into contract procedures at Metro, which has received between $4 billion and $5 billion in federal grants since 1966. Released yesterday, his report paints a picture of poor or nonexistent auditing of contracts, close relations between Metro officials and contractors and slipshod financial oversight. The report covers the mid-70s to the present.

Metro General Manager Richard S. Page, responding to the report, said Metro was aware of the gift incidents and several years ago had disciplined or fired employes involved, but he contested Welsch's conclusions on the general quality of contract administration at Metro, saying money was watched closely.

Welsch's report said: "Our survey disclosed that some officials who were recipients of gratuities have made inadequately justified and questionable professional judgements regarding those contractors who provided such gratuities," adding that further investigation is necessary.

The report named no individuals and it did not identify which contractors were involved in the gratuities given to the Metro employes. But it said that acceptance of gratuities has created an appearance of impropriety, and that lax management controls make Metro vulnerable to posssible fraud and result in "inadequate protection of the government's interest." It suggested nine specific steps by which Metro could tighten its contract monitoring, most of them focusing on stricter auditing and swift action against violations.

Page yesterday said he concurred completely with most of the steps and announced creation of three internal committees to study contract procedures and the incidence of gratuities. "We may have to strengthen our code of conduct," he told the Metro board at a meeting yesterday.

Page disputed many of Welsch's conclusions on the overall quality of contract administration at Metro, saying only a small number of contracts had been examined. "Those are atypical," Page said after the meeting. "That's not the way we normally do business . . . If the 15-year history of Metro is looked at, I think the inspector general and the public should be confident in the way we conduct our business."

Page, in a written statement to the Metro board, said two employes of the Bechtel Corp., which manages Metro's construction projects, were fired after a joint Bechtel-Metro investigation. Metro found that a contractor had paved the driveway of one of them and installed an electrical conduit to an outside barbecue at the home of the other, according to Page.

One Metro employe was fired for "being too close" to several contractors, Page said.

In 1978, about 10 Metro employes received reprimands after their names appeared on expense reports filed by a contractor, showing that the company had treated them, and in some cases their spouses, to such things as meals, golf greens fees and tickets to entertainment events, Page said.

Entertainment records show that in a period of about one year, one unidentified contractor spent at least $3,920 entertaining Metro and Bechtel officials, of which $1,789 went for two officials alone, according to the report. The report said that Metro had taken no significant action to curb acceptance of gifts and that Bechtel and Metro officials whom investigators contacted said that taking entertainment and gratuities of "minimal value" was acceptable.

Yesterday, Welsch declined to say whether any findings involving Bechtel employes were among the matters being referred to the Justice Department.

The Metro study is the Transportation Department's first application of a new program called a Fraud Prevention and Detection Survey, Welsch said. His office had no prior suspicions of impropriety at Metro, he said, but selected it because it is large and a recipient of federal grants.

Two investigators and two auditors worked full-time examining four major construction contracts chosen for their size and degree of completion, Welsch said. Numerous other contracts were examined in less detail.

Page identified the four major contracts studied as: a $34 million contract with Morrison-Knudsen Construction Co. to build the Van Ness-UDC station and tunnels around it; a $78 million contract with General Railway Signal Co. for automatic train control; an $18 million contract with the George Hyman Construction Co. for the Huntington station; and a $1 million contract with the Kora-Williams Co. to clean up tunnels and stations after construction.

Among the report's conclusions:

Metro does not require Bechtel and another consultant, DeLeuw Cather, to enforce conflict of interest codes on their employes. In his written commentary on the study, Page said Metro does in fact do that. Bechtel declined to comment. Efforts to contact DeLeuw Cather were unsuccessful.

Metro does not require reasonable supporting evidence from contractors for their cost estimates. Page wrote that "to our knowledge, we have never relied upon contractor's claims without analysis of merit and cost issues."

Metro officials make decisions without being held accountable and conduct one-on-one talks with company officials. Page responded that in some cases one-on-one negotiation is a valuable tool, but in any case agreements reached there are subject to review by others.

In contract renegotiations, final agreement on cost is first reached and "detailed cost data is then manipulated until the bottom line agreement is justified," according to the investigation. Page denied any knowledge of such practices.

Metro and Bechtel officials assisted contractors in drawing up proposals that were then submitted to them for approval. Page said Metro would look into this allegation.

Metro auditors do not have sufficient independence to be effective. Page said that his audit staff had completed more than 100 internal audits, though he said that it had not audited the Department of Design and Construction, which oversees building contracts.

In other developments, the Metro board yesterday sent a $337 million operating budget for fiscal 1983 to member jurisdictions for consideration and scheduled hearings on alignment of the proposed Green Line -- June 15 in the District of Columbia and June 16 in Prince George's County.