WASHINGTON, Sept. 21 — The Federal Communications Commission, seeking to win political support for its proposal to issue licenses for hundreds of new low-power FM radio stations, has completed new regulations that permit larger stations to raise complaints about any signal interference from the start-ups, agency officials said today.

They said the commission approved the new rules in principle on Wednesday in an effort to defuse the criticism of the plan by National Public Radio and the nation's leading commercial broadcasters.

The rules are expected to be released as early as Friday. They come in response to criticism of the low-power radio plan from broadcasters and members of Congress, who support legislation to curb the program, which would issue licenses to groups like schools, churches and community organizations.