Fianna Fáil is calling for the Central Bank to be given the power to cap interest rates on mortgages.
The Finance Minister Michael Noonan had given lenders until today to address rates which he had said were too high.
Some have made changes, but so far only AIB and Permanent TSB have tackled variable interest rates.
Fianna Fáil's finance spokesman Michael McGrath said: "It is past time for the Central Bank to be given additional powers to intervene (in) interest rate policy."
He said the party was not advocating a "free-for-all situation", but one where a test would be carried out to determine whether there had been a market failure and an absence of competition, or where it was "exceptionally difficult" to switch from one mortgage provider to another.
Micheál Martin also addressed the issue in the Dáil, telling the Taoiseach that customers were being "screwed and ripped off".
Responding to the criticism, the Taoiseach, Enda Kenny, said action on mortgage rates was "a "work in progress".