Retailers face fines of up to €3,000 for every time they fail to properly display the price of their goods.
The Minister for Enterprise Trade and Employment, the Tánaiste, Ms Harney, today announced the new regulations, which take effect from March.
"Everything from washing machines, furniture and carpets to a loaf of bread must be clearly priced," Ms Harney said, warning that the rules would be enforced.
The new law, which comes into force on March 1st, will also oblige retailers to display a unit price (for example, price per kilogramme or per litre) for all products sold by quantity.
The Tánaiste said: "I am a strong advocate of competition in all sectors of the economy. But for competition to work effectively, consumers must be able to make informed choices. This new law places the obligation on retailers to provide clear and unambiguous information as to what price they are asking the consumer to pay for any given product".
She said the new regulations would be rigorously enforced by the Director of Consumer affairs. She said she was giving retailers "ample time" to make provision for the new rules and called on consumers to be vigilant and report any breaches to the Director of Consumer Affairs.
The rules also apply to goods sold over the Internet or by mail-order catalogue but goods sold in the provision of a service, for sale at auction or works of art are exempt.
The Tánaiste also raised the possibility of making retailers announce price rises as part of future regulations.