Stephen J. Friedman, nominated to become the fifth member of the Securities and Exchange Commission, told the Senate Banking Committee yesterday that neither his partnership in a New York law firm nor his ties to the Carter administration would create conflicts for him as a commissioner.

President Carter nominated Friedman to replace former commissioner Roberta Karmel. He is a securities lawyer and a partner in the New York firm of Debovois Plimpton, Lyons and Gates. Friedman said he would resign from his firm if he is approved as a commissioner.

Committee Chairman Sen. William Proxmire (D-Wis.) generally praised Friedman's nomination but expressed mild misgivings about a possible "appearance of conflict of interest" fromf Friedman's association with the law firm and the possibility he would return there from the SEC.

Proxmire also asked Friedman whether he could maintain his independence in spite of a previous position with the Carter administration. Friedman served as deputy assistant secretary of the Treasury for capital markets policy from 1977 to 1979.

In both cases, Friedman responded that he anticipated no problems.

Friedman was highly praised by Sen. Jacob Javits (R-N.Y.), and praised by Sen. Paul Sarbanes (D-Md.) and Proxmire. Proxmire called him "extremely well qualified," with the type of experience and expertise needed by the commission.

Friedman, 42, is a graduate of Harvard Law School. He worked as a law clerk to Supreme Court Justice William Brennan from 1963 to 1964. From 1964 to 1965 he was special assistant to the maritime administrator at the Commerce Department. He joined the law firm in 1965 and became a partner in 1971, then left in 1977 to work for the Carter administration.