The Legal Services Corp. named James H. Wentzel, a Federal Trade Commission official, as its new president yesterday -- a choice that immediately drew fire from some legal aid advocates.

Wentzel is a former associate of the National Legal Center for the Public Interest, a conservative foundation that advocates curbs on government regulation and is funded in part by corporations. He was chosen for the $68,700 job after a six-month, nationwide search by the 11 LSC board members.

Clinton Lyons, executive director of the National Legal Aid and Defender Association, criticized the board of directors for choosing someone who has no experience with legal aid programs. He said this contradicted assurances voiced by several board members at their Senate confirmation hearings that, in choosing a president, they would consider such factors as experience with the LSC program and the candidate's commitment to the program and to serving the poor.

"The limited information that we have does not indicate that he meets any of those tests," said Lyons, who was LSC president in the Carter administration. "They told the Senate something different from what they actually did. They aren't looking for a person who has the ability and experience to put a corporation together that can serve poor people."

But W. Clark Durant III, a Detroit attorney who heads the board of directors, said Wentzel "can be a salesman for the program in a way that is fresh and objective and not be dismissed as special pleading. He doesn't come in with any preconceived notions about this program."

Wentzel could not be reached for comment yesterday.

Durant said that Wentzel is a conservative but that, as vice chairman of Fairfax County's Redevelopment Housing Authority, he "has tried to come up with creative solutions to help individual poor people."

Jerry Hopkins, former chairman of the authority, said Wentzel "did not display any sort of advocacy on behalf of low- or moderate-income people . . . . He wanted to maintain the status quo.

"It didn't seem to make any difference what the facts and figures were, he voted against anything unless it was for elderly housing -- that's the only thing he was predisposed to support," said Hopkins, a Democrat.

One Fairfax County supervisor, who asked not to be identified, said Wentzel was a "source of constant frustration. He was a totally negative voice. He was so clearly negative on all subsidized-housing programs."

President Reagan has repeatedly tried to abolish the LSC, a semi-independent corporation responsible for providing legal assistance to poor people.

Wentzel has been assistant director for litigation at the FTC's Bureau of Competition since 1982. He was in the Justice Department's legislative office from 1973 to 1979 and worked for the Denver district attorney after graduating from the University of Denver College of Law.

Several current and former FTC officials sharply criticized Wentzel's record at the agency. "He didn't have any knowledge of antitrust law, had no understanding of administrative processes at the commission and seemed to have no interest in gaining any," a former official said.

In a 1980 article for the National Legal Center, Wentzel criticized minority set-aside contracts in small business and public works programs. He wrote that "government benefits have been bestowed to 'minorities' rather than individuals." He said Congress has "made a mockery" of equal opportunity "by mandating government preferential treatment and benefits to certain minority groups, to the exclusion of all other persons in the nation."

In a related development, Wilbur Colom, a Mississippi attorney who was considered for the LSC job, has charged that board members questioned him about his religious background and church attendance during an interview in Washington.

Colom, who is now out of the country, told the Oxford (Miss.) Eagle: "There are some right-wing ideologues who feel the LSC has the role to teach morality to the poor and to teach Christianity to the poor . . . . When they asked about my church attendance, I asked, 'Is there a religious test for government jobs now?' and that kind of shut off the conversation."

Chairman Durant said he could not recall anyone asking such questions, which he agreed would be improper.