40 enforcement actions were taken against 33 traders last year by the Competition and Consumer Protection Commission (CCPC).
24 retailers were issued with 27 €300 fixed payment notices for breaching price display legislation, while seven traders were given compliance notices for charging customers more than the price displayed.
In one case, the Sligo-based McCormack Car Sales was required to provide an undertaking to the CCPC after giving false and misleading information to a consumer in relation to the mileage of a car.
The company also compensated the affected customer to address the breach.
In another instance, Lifestyle Sports received a fixed payment notice for not reimbursing delivery costs to customers who cancelled their order or returned a purchase under the Consumer Rights Directive (CRD).
The sportswear company also received a compliance notice for failing to provide information to consumers about their right to cancel a distance contract.
Meanwhile, Powercity received two compliance notices for providing customers with misleading information on their legal rights, and failing to provide information rights to cancel a distance contract.
The CCPC carried out 150 unannounced inspections of trader premises across Ireland in 2016.
Chairperson of the CCPC Isolde Goggin said the latest Consumer Protection List shows "traders need to comply with consumer protection law and if they do not, the CCPC will not hesitate to take enforcement action up to, and including prosecution".
She added: "Our nationwide inspections led to 27 fines being paid by traders who failed to display prices.
"In 2017, we will be continuing our unannounced inspections of retailers across Ireland and we will take appropriate enforcement action against retailers who fail to comply with pricing legislation."
