Wholesale prices, an indicator of prices consumers eventually pay, soared 1.1 per cent in March for the fastest one-month climb since October, 1975, the Department of Labor reported yesterday.

The March increase followed a large, 0.9 per cent jump in wholesale prices in February and adds to worries that the nation is back on the road to accelerating inflation.

Much of the increase had been expected by economists, because of the crop-destroying freeze of January and February that showed up as a 2.5 per cent increase in farm product prices during March.

But there was also a big, unexpected increase in industrial prices such as metals, lumber and transportation equipment, which econimists did not expect.

The big increases in February and March wholesale prices were matched by similar large increases in consumer prices, which jumped 0.8 per cent in January and 1 per cent in February.

White House spokesman Rex Granum said that most of the food price increases are due to the winter weather and sharply increasing imported coffee prices. He also said that the sharp rise in energy prices is in part attribute to the cold weather.

"We do not believe that the underlying rate of inflation is increasing," Granum said, noting that other indicators of rising cost pressures, such as accelerating wage increases, are not present. Administration economists contend that the underlying inflation rate is between 5 and 6 per cent.

If the March wholesale price rise continued for a year, prices would be 14 per cent higher next March.

Opponents of President Carter's tax rebates are sure to cite the acceleration of wholesale and retail prices as another reason to defeat the S50-a-person payouts. The President's economic stimulus package has bogged down in the Senate and his rebate proposal is in trouble, administration officials agree.

The dismal performance of the stock market in the past several months has been blamed in large part on fears in the financial community that big increases in inflation are on the horizon.

While the announcement of the March wholesale price increase temporarily depressed stock prices yesterday, the Dow Jones Industrial Average closed up 4.15 points on the day.

The Labor Departments wholesale price index stood at 191.9 per cent of its 1967 average, which means that a selection of goods that cost businessmen $100 in 1967 cost them nearly twice as much - $191.90 - in March.

Alan Greenspan, chairman of the Council of Economic Advisers under President Ford and now head of the New York economic consulting firm of Townsend-Greenspan, said that while the accleration of industrial prices was disturbing he found no evidence to say double-digit inflation was back again.

Without acceleration in wage costs or import prices, there is no reason to think that the recent increases in wholesale prices are signalling big inflation surges, Greenspan said.

If wage settlements start to pick up and the non-food portions of the consumer price index begin to accelerate, "then we should start getting a little concerned," Greenspan said. But he said recent price reports confirm that the nation will make no further progress in its fight against rising prices for some time.

Van Doorn Ooms, chief economist for the Senate Budget Committee, said that because the inflation is still largely in the food area, where supplies can be expected to increase soon, there is no reason to anticipate big price rises to continue.

Nearly all farm product prices increased in March, with coffee leading the way. Grains, fresh fruits and vegetables and cotton also rose. Poultry and egg prices declined.

Fuel prices rose 1.4 per cent, less than the 3.3 per cent rise in February. Because there is a delay in reporting gas and oil price increases, the March fuel price rise reflects developments in January and February.

When fuel price increases are excluded, industrial prices till rose 0.7 per cent in March, up from 0.2 per cent in February and matching the 0.7 per cent January rise. Economists are concerned more about industrial prices than farm prices because increases in industrial prices are less likely to reverse themselves.

All percentage changes are adjusted by the Labor Department to account for seasonal variations, although the wholesale price index is not.