Opposition Leader Tony Abbott says he thought it was "odd" that Kevin Rudd turned up to their first election campaign leaders' debate with a stack of notes.
The prime minister has been accused of cheating by using notes during Sunday's debate, in breach of the agreed rules.
Mr Rudd's office quickly issued a statement denying any deliberate wrongdoing, saying he had no intention of breaking the rules and no objections were raised at the time.
Mr Abbott confirmed on Monday he was told not to bring any notes.
"I was interested to see that Mr Rudd turned up with a big wad of papers and he did seem to be reading his opening and his closing statements," he told Gold 104 FM radio in Melbourne.
"It did strike me as a little odd, given that they were the rules, that he brought all those papers in."
But he said the important thing was that both of them were able to talk to the people about their plans for the future.