The Attorney General's Commission on Pornography has tentatively decided to recommend a wide-ranging government crackdown on obscene material, including an attack on X-rated films by means of laws against pandering and prostitution, according to a highly critical report released yesterday.

The American Civil Liberties Union, which has frequently questioned the commission's objectivity, described its proceedings as biased, unfair and "intellectually indefensible" and said the chairman, Arlington County Prosecutor Henry E. Hudson, has advocated "extreme measures" while paying scant attention to privacy and First Amendment concerns.

Hudson replied that the 12-member panel has taken a balanced approach and has made "a scrupulous effort" to hear witnesses on both sides, but that many invited witnesses declined to appear.

"Every diverse viewpoint is being argued and seriously considered," he said. "There have been no final conclusions and no findings of fact . . . . I think it's premature to comment until a final report is filed" in June.

The ACLU, citing transcripts of meetings, said the commission has tentatively voted to approve a number of antipornography measures. According to the report by ACLU legislative counsel Barry W. Lynn, these include:

*Adopting forfeiture laws to seize the assets of any business that sells obscene materials. The ACLU said this "could permit the seizure of an entire commercial store if it profited by the sale of a few 'illegal' magazines."

*Using pandering and prostitution laws against producers and casts of X-rated films.

*Declaring the transport of obscene material a federal crime whether or not a state line is crossed.

*Giving obscenity prosecution a higher priority for U.S. attorneys and local law enforcement officials.

*Using federal and state antiracketeering laws to seize pornographic materials.

*Defining child pornography to include the use of models under 21.

Removing doors on film booths in adult bookstores.

*Making possession of child pornography a federal crime.

The commission narrowly rejected a proposal to treat dildos and vibrators as obscene devices but Hudson said the issue would be raised again next week, according to the report. The panel is also scheduled to consider measures restricting pornography on cable television, "Dial-a-Porn" telephone messages and computer services offering pornographic information.