The chairman of the National Iranian Oil Co. said today that the new revolutionary governemt to longer would deal with the Western oil consortium that has been producing and exporting most of the country's oil for 25 years.

The statement coincided with a radio address by Ayatollah Ruhollah Khomeini, the spiritual leader of the Iranian revolution, calling on followers to "root out" the remnants of "American, British and Zionist colonialism" in Iran.

Speaking on the eve of a planned trip to take up permanent residence in the hold city of Qom, 90 miles south of Tehran, Khomeini also delivered a thinlyveiled broadside against Iranian left-wing groups, which have built up a considerable following in the southwestern oil fields.

National Oil Co. chief Hassan Nazih, just back from the south, expressed concern about leftist influence as well, telling a meeting of about 1,00 employes not to let "ideological problems" interfere with the company "reorganization." Apparently he was referring to leftist demands -- so far opposed by the government -- to elect the management of state companies.

Most of Nazih's speech amounted to a xenophobic tirade against to West and seemed to be for the consumption of the most radical Iranian oil workers. Political observers said it was unclear how much of the rhetoric would actually be translated to reality over the long haul.

Taken a face value, Nazih's remarks mea the abrogation of a 20-year agrement with the Londonbased consortium, known oficially as Iran Oil Participants, Ltd. Formed a quarter century ago, the consortium signed a new agreement with Iran in 1973 but it soon became obsolete and both sides repeatedly violated it while trying unsuccessfully to negotiate a new one.

"The word consortium will, with Allah's help, be eliminated from Iran's oil vocabulary," said Nazih, a close associate of Khomeini.

The new government will cut its ties with the foreign companies that have "imposed themselves" on the national company, Nazih said, referring to the consortium. "We are now telling them to get out before they are expelled."

Nazih also denounced the "13 companies which have been plundering Iran." In fact, there are 14 firms in the consortium, led by British Petroleum with a 40 percent shareholding. He described the consortium as "strangling the throat of Rian." But, he said, "now we are cutting off those fingers."

If Iran does cut all ties with the consortium it will repeat Iraq's nationalization of foreign oil operations. But in practice, Iraq -- for all its heady rhetoric -- continues to sell much of its oil to the major companies.

In the recent slack oil market, Iraq even had t shave prices, underselling other oil cartel members, because the major companies tended to favor oil from states where they produce it.

Nazih later indicated his company was willing to deal indivdually with consortium companies, although not as a group under the existing agreement -- which gives the firms a discount of 22 cents per barrel on the oil they buy.

Nazih said Iran's target for oil production and export would only be revealed after Irn starts selling crude Monday after a two-month halt.

Iran hopes to get $18- $20 a barrel, about 30 percent more than the contract price fixed by the Organization of Petroleum Exporting C ountries, although some experts have expressed doubts much oil can he sold at the premium price.

Nazih later indicated his company had assured him they could raise production to Iran's pre-strike level of nearly 6 million barrels a day. Full capacity is 6.5 million. Industry sources have said Iran would be hard pressed to produce more than 4 million barrels a day without the help of foreign workers.

The Iranian chief of exports and marketing, Reza Azimi, said the government would decide over the weekend how much oil to produce, but that for the first several weeks it probably would not top 2 million barrels a day. At that level about 1.3 million would be available for export.

Azimi said Iran would not discriminate against the consortium members -- which include 11 American companies -- in sales to individual firms. He said customers "can be anyone in the world. We don't have any restrictions except against Israel and South Africa."

Azimi said Iran would only sell oil on a spot basis, rather than under longer-term contracts, while production remains limited to less than 2 million barrels a day. He said that the price on the spot market for Iranian crude "should be more than $20 a barrel," possibly up to $23 a barrel for Iranian light.

"Nobody is selling at OPEC prices these days," because of the world's oil shortage, he said.

In his radio speech Khomeini called the "expulsion of foreign hands" one of the main goals of the Iranian revolution. "The shah handed this nation over to foreigners and we came under the economic, military and cultural domination of American, he said.

But other Khomeini remarks were apparently directed at Iranian Marxists, who have been marking inroads with Iranian workers and defying his efforts to rebuild the army ahd turn the country into a full-fledged Islamic republic.

"Now I see that there are some groups that want to bring back the hand of the foreigner, his looting and his strangulation, in a new from Khomeini said. "We must isolate them and foil their propaganda."