The White House, moving to avert a possible election-year fight with business and labor, yesterday extended its current wage-price guidelines indefinitely, rather than revise them by Oct. 1 as scheduled.

At the urging of unions and management, the Council on Wage and Price Stability issued "interim final" standards that continue the present guidelines at least through 1980 -- and possibly for another year, as well.

Yesterday's announcement stemmed from an agreement worked out earlier between Alfred E. Kahn, the president's chief inflation adviser, and leaders of the administration's tripartite pay and price advisory committees.

Business and labor both had wanted the guidelines program dismantled, while the White House argued strongly for toughening the pay and price standards. As a compromise, the three sides agreed to postpone any decision until 1981.

The new standards essentially continue the 7.5 percent-to-9.5 percent pay guideline that has been in effect since October 1979 and a series of complex pricing rules designed to hold increases to the averages of 1976-77.

The administration also announced two minor changes in its price guidelines -- one liberalizing calculation rules somewhat for petroleum refineries and another intended to reward firms that invest in new plants or equipment.

Ironically, the change involving the petroleum refineries would have made the Mobil Oil Corp. in compliance with the price guidelines had it been in effect when the firm was cited as a violator last spring.

Mobil had contended at the time that it actually would have been in compliance had its gross margins been calculated on a year-over-year basis rather than quarterly, as the wage-price council had.

However, the White House, anxious to appear aggressive in enforcing its guidelines, threatened to deny Mobil federal contracts. The administration eventually agreed on a token settlement.

The guidelines changes announced yesterday would:

Judge compliance by petroleum refineries on the basis of their gross margins over a full-year period, rather than on a quarterly test, as the wage-price council had imposed before.

The council said the change was made to "encourage the use of lower-cost crude oils and to provide an incentive to upgrade product mixes." It asserted that the revision "promotes national energy goals and needs."

Allow firms extra credit in calculating their profit limitations to allow them to reap the benefit of any cost-savings that result from investments designed to increase company productivity, such as new plants and equipment.

Critics had charged that the council's previous regulations were so inflexible they often tended to discourage firms from making such investments.Officials said companies would have to document any cost-savings they claim.

The decision to continue the existing guidelines beyond the November election marked a departure from the schedule that the White House had announced previously.

Top administration officials had intended earlier to unveil a new set of standards Oct. 1 that would have stiffened the previous guidelines. Without yesterday's action, the current guidelines would have expired Sept. 30.

Next month will mark the beginning of the third year of the voluntary wage-price guidelines. The program was begun in October 1978 after it became obvious that previous anti-inflation efforts had failed to slow prices.

Besides averting a possible pre-election flap, sources said the decision to postpone the new guidelines also will give the winner of the coming presidential election more flexibility in deciding the program's fate.

Republican presidential candidate Ronald Reagan has said he plans to eliminate the guidelines program, and business and labor both want the standards phased out.