Skyrocketing, frequent increases in manufactured wallboard prices should be investigated by the federal government, gypsum drywall contractors said here this week.

Citing a study of price increases reported by contractors, the association representing wall and ceiling drywall contractors said that prices of the gypsum products increased an averaged 43 percent in 18 months.

Joe Baker Jr., executive of the Washington-based Wall and Ceiling Contractors/Gspsum Drywall Contractors International, added that wallboard increases were 14 percent more than those for lumber, 28 percent more than for concrete and 31 percent more than for insulation in that period. He cited Labor Department statistics.

However, a spokesman for U.S. Gspsum Co. the nation's largest producer of wallboard used in both commercial construction and houses, said the firm's prices had gone up 57 per cent since 1967 while costs were increasing 98 percent.

John Bush Jr., Washington representative for U.S. Gypsum, added that the cost of energy used in producting gypsum wallboard incresed 233 percent since 1967 and that facilities were expanded to meet the heavy demand from the housing industry in the past three years.

He also cited wholesale price index figures from the Labor Department showing gypsum products rising 29 percent in the past year, second only to general millwork (30 percent). But he pointed out that the index related to a 1967 base showed gypsum prices now within 2 points of the level for all construction materials and less than those for lumber, cement, paving and several other materials.

But the association insisted that drywall manufacturers are raising their prices so often and so much in recent months that it is difficult for contractors to bid on jobs.

Contractor Frank Krafft of Alexandria said: "We must pay the price charged at the time of delivery and those prices have "gone hog-wild recently." Another area contractor, Connie Coakley, said that Drywall material price increases averaged only 2 percent annually until 1976 but "have blown us out of the water in the past year."