Communists are effectively banned from holding high office in Iran's new Islamic republic, according to the second installment of a purported draft of its constitution published today.

Information Minister Nasser Minachi, a member of a committee charged with drawing up the document, confirmed that the articles published unofficially for the past two days in the Tehran newspaper Kayhan were generally accurate. He cautioned, however, that the constitution described was not the final draft.

Nevertheless, the draft published yesterday and today gives Iranians their first glimpse at how the government will operate under the Islamic republic, whose governing bodies and system had not previously been defined.

After reading the draft, one Iranian constitutional scholar said today that many of the new articles appeared to be less liberal and put greater restrictions on freedoms than the 1906 constitution, which was scuttled along with the Iran monarchy earlier this year.

The 1906 constitution, however, was generally ignored and repeatedly violated by Shah Mohammad Reza Pahlavi and his father, who started the short-lived Pahlavi dynasty in 1926. Like the present draft, the earlier document provided for a body of religious leaders to rule on the Islamic acceptability of laws, but it also provided for a consitutional monarchy which soon assumed dictatorial powers.

According to Kayhan's version, the draft stipulates that the president of the Islamic republic must be a Shiite Moslem - the sect to which 95 percent of Iranians belong - and at least 40 years old. He must be a "nationalist" without any leftist or rightist political affiliation and cannot be "a follower of any misleading ideology."

Observers noted that this has been the term used by Iran's conservative Moslem clergy to describe Marxism and other leftist philosophies.

Information Minister Minachi appeared to confirm the inference that this clause effectively bans Communists when he said authorities would "never allow a person who is against the Islamic religion" to hold high office.

"This is a religious and Islamic revolution and government," he said in an interview. "We have the right not to allow them . . . The Moslem majority have the right to keep the government for themselves."

According to Minachi, Ayatollah Ruhollah Khomeini, the spiritual leader of the present provisional revolutionary government, will have no official role under the new constitution. Yet the information minister held out the possibility that Khomeini would continue to "advise the government" in an unofficial capacity after a permanent administration takes power.

"It is only in the present revolutionary situation that he is insisting on guiding and protecting the government," Minachi said. "At the time of the transfer to a permanent government, this will be finished."

Minachi said the final draft of the constitution would be officially published in newspapers next month. Then, he said, the public would have two months to submit recommendations to a special commission. After that, elections for a consistuent assembly would be held. The assembly would take the public's recommendations into consideration and ratify a final, possibly amended, document.