Clear card charges have jumped from 13.8pc to 17.8pc, Platinum card rates have gone up from 16.6pc to 17.3pc and the Classic card has increased by 2pc to 19.9pc.
Bank of Ireland, which has already cost cash-pressed taxpayers €4.7bn, has justified the interest hikes, saying they were "necessary to sustain product investment".
But Consumers Association boss Dermott Jewell has accused the bank of making "a determined calculation to take advantage of people".
"They are going to make a significant amount of money in interest and it comes across as calculated.
"Its a terrible time to introduce increases in credit card interest rates. There is an argument there's never a good time -- but there is and this isn't it".
Fianna Fail social protection spokesman Willie O'Dea described the hike as "an ambush on consumers".
"It's just a device to take more money from consumers during this vulnerable time," he said.
Finance expert Simon Moynihan, of price comparison site bonkers.ie, has also accused the bank of squeezing shoppers at their most vulnerable.
"The bank knows people will blow a chunk of cash at Christmas and hope to be able to pay back in January, but few will be able to clear the debt in January. It seems to be a way for the bank to make an extra few quid".
Trinity College economist Constantin Gurdgiev said it was only a matter of time before other banks follow Bank of Ireland.
"The amount of the increase is very significant and it is certainly going to put a lot of pressure on households who have the most unsecured debt."
A bank spokeswoman said: "It is over 12 months since we last increased credit card interest rates". The latest hike was necessary because of "continued pressure from high funding costs and the continuing high risk and loss profiles".
SINEAD RYAN: PAGE 16