Sinn Féin says it is to bring forward legislation that would outlaw the practice of dual or differential pricing in the insurance market.
It follows a decision by the regulator in the UK that it will move to ban the practice that involves insurers differentiating between customers for reasons other than the expected cost of claims and expenses.
Under plans announced by the Financial Conduct Authority (FCA), firms would be free to set new-business prices.
But they would be prevented from gradually increasing the renewal price to consumers over time - known as "price walking", other than in line with changes in a customer's risk.
The FCA previously identified six million policyholders were paying high or very high margins in 2018.
Sinn Féin has been waging a campaign to have the practice banned, arguing that it targets vulnerable, elderly and low-income groups.
The Central Bank is currently conducting a review of the issue, and recently it said it is concerned about weaknesses it has identified in the pricing practices used by some insurance companies.
The bank found that some firms may not be adequately considering the effect of their pricing practices on their consumers, potentially leading to poor customer outcomes.
An analysis conducted in recent months by the bank established that while some firms claim they do not use differential pricing, the majority of firms do actually utilise it through various techniques.
"Irish customers cannot afford to wait another year for the Central Bank to finish its review," said Pearse Doherty, Sinn Féin's finance spokesman.
"What we need is immediate action - dual pricing must be banned. It is as simple as that."