Waiting lines for gasoline are almost certain to reappear once the economy begins to improve, according to the Central Intelligence Agency.

An economic upturn will stimulate greater demand for gas and set consumers scrambling for increasingly scarce supplies, the CIA predicted in a generally gloomy forecast of the world oil market for the next three years.

Oil price hikes will come in "spurts" as industrial nations compete for insufficient fuel supplies, according to the report, the agency's first major assessment of the world oil situation since 1977. A copy was made available to the Los Angeles Times.

"No matter how events in 1979 sort themselves out, the outlook for oil supplies over the next few years is poor," the study said. "Total oil supplies available to the Western countries are unlikely to increase significantly and may well fall."

The CIA reported that:

U.S. petroleum production will keep dropping despite removal of price controls on crude oil.

The Communist bloc, which now sells surplus oil to non-Communists countries, will become a net importer during the next three years.

The organization of Petroleum Exporting Countries will not increase production regardless of rising demand.

Mexico's oil production will grow until the mid-1980s, but will then slow to avoid inflationary disruption of the economy that could be triggered by burgeoning revenues from oil sales.

Demand for oil will slacken temporarily because of the huge increase in price -- 60 percent since Jan. 1 -- and the recession now developing in the United States, it said.

"Thus, weak demand may temporarily create the illusion of ample oil supplies, masking once again the longer-term energy problem," the CIA said. "But softness in the oil market is unlikely to last long; a recovery of economic growth would quickly tighten the market and again push up oil prices unless major improvements in conservation have been achieved."