Various demonstrations are scheduled here by groups opposed to the U.S. government's handling of the hostage situation, to the Iran government of Ayatollah Ruhollah Khomeini, and to pro-Khomeini demonstrators.

Law enforcement officials said yesterday that based on application permits, the largest of these is expected to be that of a group calling itself "Americans Against Iran," which has received permission to demonstrate Saturday morning.

The head of this organization, 29-year-old stockbroker Mark James, said it is an ad hoc collection of grass-roots Americans who will rally to demand the immediate release of American hostages in Iran, as well as the deportation of "Iranian agitators" here. He said his group expects up to 10,000 people to participate at the Washington Monument grounds.

Others who have received permits include the Iranian Democratic Party, which is expecting 7,000 at a rally on the monument grounds Aug. 31 to introduce the leaders of an anti-Khomeini "shadow government" here, and the Concerned Americans March to Free the Hostages, which has a rally approved for Sept. 20.

The demonstration by James' group is the first organized effort by Americans here to protect tactics of Iranians, police said yesterday.

In recent weeks a number of Islamic groups have held demonstrations in support of Khomeini, and increasing numbers of Americans have lined the parade routes to jeer.

James said yesterday that it occurred to him a couple of weeks ago "that Americans had done nothing to organize a peaceful demonstration to let the (U.S.) administration know we're not satisfied with the way the hostage situation has been handled."

He and colleagues at his brokerage firm have handed out flyers and appeared on local television this week advancing their rally, which is to begin at 10 a.m. on the monument grounds.

The existence of the Iranian Democratic Party was announced yesterday at the National Press Club by one of its leaders. Ferydoon Khoee, who said the group expects to be the umbrella for all anti-Khomeini Iranians in this country.

Khoee said his group is opposed to the "tyranny" and "dictatorship" of the Khomeini regime and is committed, through a countrywide intelligence apparatus here and short wave radio broadcasts beamed into Iran, to establish a democratic government there. The group has received permission to hold rallies from 4 p.m. to 7 p.m. on Sept. 30 and Oct. 31 as well as Aug. 31, all on the monument grounds.

Lorraine Ramos, one of the leaders of the Concerned Americans March to Free the Hostages, said the group's Sept. 20 rally on the Mall is being organized because "we were sick and tired of seeing the Iranians out there demonstrating. We want to get Americans out there."