Trade and enterprise minister Mary Harney has called for retailers to "display a price per litre for a product sold in a one-and-a half litre pack, and similarly show the per kg price for other products".
She said such regulations would ensure that "consumers have the necessary information to compare prices between outlets, product brands in a particular outlet and different sizes of a branded product". The rules would be "rigorously enforced,"she added.
The move follows protests from the Irish Consumers' Association over rising grocery prices after the conversion to the euro and threats of a Greek-style "buy nothing day".
However, the minister ruled out any return to price controls to curb inflation, which is now almost 5%, and insisted the answer lay in greater competition and consumer choice.
Tesco said it would welcome "in general" any move that encouraged clarity on prices.