Despite the biggest Reserve Bank cuts to official rates in years credit card holders are being charged with higher interest fees.
Treasurer Wayne Swan has demanded an explanation as to why banks have not passed on the savings to their customers.
Despite the fact that the RBA has slashed the cash rate by 3 percent since September, the rates on most credit cards have not been reduced in fact on some products the rates have risen.
The consumer group's trace of 140 credit cards issued by banks, credit unions and building societies has found rates had fallen just 0.28 percent on average since September - less than a 10th of the Reserve's cuts.
The ANZ were the only bank to pass on the full 1 percent cut to their credit card holders.
The Commonwealth Bank will cut their rates on all cards by 0.4 percent from 19th of December.
Australian's owe almost $45 billion on credit cards with some paying interest charges of up to 20 percent, which is nearly five times the official cash rate.