Two more of the nation's biggest roasters raised wholesale prices on ground coffee by 25 cents to $3.08 a pound yesterday and blamed the rising cost on a frost that damaged the Brazilian coffee crop.

Consumers should find the latest price hikes reflected on supermarket shelves within three to four weeks, the current lag period before wholesale price changes reach the retail level.

General Foods Corp.'s Maxwell House division, the No. 1 roaster, announced yesterday it was increasing the list price of its Maxwell House ground coffee to $3.08 a pound from $2.83 a pound, and Hills Bros. Coffee Co., the No. 3 roaster, said it was boosting the price of its ground coffee by 25 cents to $3.08 a pound. Both actions are effective immediately.

General Foods, based in White Plains, N.Y., also raised prices on its instant and freeze-dried coffees, which are sold under the Maxwell House, Maxim, Sanka and Brim labels, by between 3 cents and 3 3/4 cents an ounce - depending on brand.

Hill Bros., headquatered in San Francisco, raised the wholesale price of its high-yield coffee by 25 cents to $2.53 for a 13-ounce can, but held the line on its instant coffees.