The publisher of Washingtonian magazine filed a suit in D.C. Superior Court yesterday asking that public television station WETA be restrained from funding or participating in the publication of a new monthly magazine that will complete with Washingtonian for advertising.

Publisher Phillip Merill, who is also a contributer to WETA, asked to court to step in to protect him from immediate injury, including the possibility that WETA's role in publishing The Dial ultimately might cost the public broadcasting station its license.

"That's the most cockamamie idea I've ever heard of," said WETA President Web Chamberlain, who said he was not worried by the lawsuit.

The move was the latest in a series of actions by Merill, who says he is the "point man" for a coalition of magazine publishers opposing what they say is direct and indirect government funding for the magazine, which is scheduled to appear Sept. 1.

The magazine will have an initial circulation of 650,000 subscribers to the four major television stations that are publishing it. Besides WETA they are WNET in New York, KCET in Los Angeles, and WTTW in Chicago.

"We'll let the courts determine how it will come out," said Chamberlain. "It wouldn't concern us at all except for running up legal fees. Phil Merrill's been very helpful," he said. "All this publicity has been terrific."

Merrill has also filed a petition with the Federal Communications Commission asking that WETA be barred from promoting The Dial on television. Chamberlain said that the station would no promote the publication by name.

Merrill's arguments against WETA's involvement in publishing the magazine include charges that it violates FCC rules and the TV station's charter. In the lawsuit, Merrill's attorneys argue that the magazine will be financed by public money.

Merrill aslo has argued that the magazne will be subsidized indirectly by taxpayers because of the tax-exempt status of the corporation that will publish The Dial.

Still Another contribution of federal funds to the publication of the magazine is through the involvement of Chamberlain and other WETA staff.