The Federal Reserve Board reported yesterday that industrial production skidded 1.9 percent last month, the most since the onset of the 1974-75 recession and a further sign that this recession may be more serious than expected.

New figures also showed that housing starts fell 2.1 percent in April. However, that was less than the 21.8 percent recorded in March, suggesting that the housing industry may be leveling off.

The combination of figures heightened concern by economists that the recession may prove more severe than the "short and mild" one that the Carter administration has predicted.

The decline in industrial production was spread throughout the economy. Two weeks ago, the Labor Department reported that the nation's unemployment rate shot up from 6.2 to 7 percent in April, the most since early 1975.

The figures came as the Federal Reserve Board reported that the nation's money supply, which had been shrinking far more rapidly than the Fed intended, exploded last week and rose $5.8 billion, the largest increase on record.

However, analysts warned that the figures may be skewed because of technical factors and may not represent a relaxation of the Fed's tight-money policies. Even with last week's jump, the growth of the money supply still is within targets.

The April plunge in industrial production followed dips of 0.7 percent in March and 0.2 percent in February. The index, which measures the output of factories, mines and utilities, stands 2.9 percent below its March 1979 peak.

Although the sharpest declines came in the auto and construction industries, there was a visible worsening in virtually every major sector of the economy. Output of consumer goods plunged a full 2 percent.

The decline in housing last month left overall starts at a seasonally adjusted annual rate of 1.019 million units, down from 1.041 million in March. That is 41.8 percent below the 1.75-million-unit rate recorded a year ago.

The department reported that permits for new housing units, a bellwether of trends -- fell 14 percent in April to 41.3 percent below their level a year ago. However, starts of single-family homes recovered some, rising 1.6 percent.

Analysts were divided over the significance of the April figures. William A. Cox, the Commerce Department's deputy chief economist, said the smaller dip in April showed that the housing slump has "got to be close to bottom."

However, Michael Sumichrast, economist for the National Association of Home Builders, said the slippage in building permits foreshadows still more declines in starts in coming months, and shows that the market will continue to be soft.

The April rate for single-family starts was the lowest since January 1970, and marked the fourth worst month since the government began keeping records in 1959. Starts of multifamily units fell 7.5 percent.

The $5.8 billion rise in the basic money supply left the overall figure at $371.2 billion. A broader measure, which includes money in circulation and checking deposits at banks and thrift institutions, rose $5.6 billion to $388.6 billion.

Meanwhile, Charles Brown, chairman of the board of the American Telephone & Telegraph Co., predicted yesterday that the current recession will not be as severe as the 1974-75 slide.