Two Prince George's County legislators who represent areas adjacent to the District of Columbia said today they are concerned that Gov. Harry Hughes' proposals to raise the tax on liquor could make the county's privately owned liquor stores less competitive than those nearby in the District.

Currently, Maryland and the District impose a $1.50 tax on a gallon of "distilled spirits." But the budget Hughes has proposed for next year (fiscal 1984) calls for increasing that tax by 25 cents, to $1.75 a gallon, and the Prince George's legislators are concerned that the boost in price, if approved by the legislature, could drive booze buyers into the District.

"My legislative district is right on the District line and it the tax increase would put the liquor stores in my area at a competitive disadvantage," said Del. Thomas Mooney (D-Prince George's). "Right now we have an even-dollar relationship with the District," said Del. Timothy F. Maloney, who like Mooney represents the 21st district, which borders the District. "Around Christmastime you may have people driving down to Eastern Liquors to save some money on volume purchases."

According to Marvin Bond, a spokesman for the comptroller's office, D.C. and Maryland have had similar tax rates on liquor for a long time. Several years ago, Bond said, the city government increased its tax to $2 but lost so much business that very quickly it reduced the rate again to $1.25.