The coalition has accused Kevin Rudd of cheating in the first leaders' debate of the federal election campaign.

The prime minister on Sunday appeared to use notes during the debate against Opposition Leader Tony Abbott at the National Press Club in Canberra, 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.

But the coalition's campaign spokesman Mathias Cormann said it went to Mr Rudd's character that he chose to bend the terms of the debate.

"He says the election is all about trust and then he cheats in the debate," Senator Cormann told ABC radio on Monday.

"Last night Tony Abbott was looking like a leader, Kevin Rudd was looking like a reader."