Since the over-throw of the Iran's shah, South Africa has had to go to the expensive "spot" market to maintain its supply of imported oil.

Embargoed oil from Nigeria and the Arab states still manages to finds its way here through multilayered, complicated dealings of the intenational spot market, but at a premium of several dollars a barrel above established world market prices.

For years, Shah Mohammad Reza Pahlavi supplied 90 percent of the oil needs of South Africa, the coountry where the shan's exiled father died in 1945.

Most of the Arab countries have observed an oil embargo against South Africa since the 1973 Middle East war, when Pretoria assisted Israel by sending a token supply of arms.

One of the first decision announced by Ayatollah Ruhollah Khomein's new government was that Iran would no longer well oil to South Africa or Israel.

Because of the current tight world oil market, South African buyers are forced to pay handsome premiums on their spot purchases - those made out side established long-term channels according to government and industry sources. To pay for these premiums the government has raised the price of gasoline 38 cents a gallon there may be more increases later this year, sources say.

In additon, the government has set up a four-man committee to approve or reject all intended spot purchases of oil in order to pressure the importers (mainly the oil companies) into shopping around to get the lowest premiums.

The major companies (Esso, Caltex, Mobile, Shell, BP and Total) are also depending on their parent firms for additonal supplies and those that have access to non-embargoed oil such as that from Venezuela and the Noth Sea, are in the best position to heop their South African subsidiaries, according to one expert on the oil supply.

"sometimes we live day to day." said one oil importer, "but there is no crisis."

While the government is concerned about the Iranian shutoff, the consensus is that South Africa will continue to get the oil it needs - although at a cost.