Mr Andrews dismissed Mr Baillieu's comments on Tuesday and declared voters were not interested in the broadcast of private conversations or how the audio between Mr Baillieu and Sunday Age state political editor Farrah Tomazin was obtained.

Mr Andrews' leadership has been tested by the crisis, with some in his party criticising his handling of the events and the damage it could inflict on Labor's chance of victory at the November election.

“My judgment is that the people of Victoria will be focused on those things that matter so much to them - schools and hospitals, roads and public transport, whether they’ll have their job at Christmas,’’ Mr Andrews said.

The alternative premier broke his silence on Monday, admitting his staff had listened to a recording on a misplaced Fairfax dictaphone. But he said he was satisfied no one in his office was responsible for the distribution of the confidential recording.

Labor party officials Noah Carroll and Kosmos Samaras, as well as Mr Andrews' chief-of-staff John McLindon, have admitted to listening to the dictaphone's contents, but deny passing the audio onto other people. Mr Samaras destroyed the dictaphone.

Mr Baillieu, who has remained relatively quiet since his private conversation was emailed to hundreds of Liberal Party members and MPs, joined Premier Denis Napthine for an Anzac centenary event at Patterson River Secondary College on Tuesday and told reporters Mr Andrews' admission raised more questions than it answered.

"I don't think anyone could take that story with any credibility whatsoever," Mr Baillieu said. "Let's face it, senior people in the Labor Party have known for more than two months that they were an integral part of what, by any measure, was an unlawful act and they have said nothing."

He said Labor's story was implausible and the party had no credibility while Mr Andrews remained its leader.

He also said it was "blatantly obvious" that Labor knew what was going on because it failed to ask any questions in Parliament about the scandal last month when the audio - "the biggest issue of the day" - first hit. "They have been right in the middle of this from the start."

Dr Napthine said Mr Andrews' version of events "completely failed the believability test".

"It is disappointing that Daniel Andrews couldn't say why the dictaphone wasn't simply returned to its rightful owner," he said. “If it looks like a theft, smells like a theft, I think it’s a theft.”

The Premier also said if any of his staff had acted in this way they would be sacked.

Mr Andrews said he received no advice not to ask questions about the tape in Parliament when the tape emerged on June 24. On that day, Labor focused all of its five questions on ambulances. He said Mr Baillieu's comments were typical of a partisan politician trying to seize an advantage.

On Monday, Mr Samaras, who is Labor's assistant state secretary, admitted listening to the dictaphone of an Age journalist after it was handed into the lost property section at the party's state conference in May.

The Liberal Party is investigating, with a source saying party officials were trying to marry up some of the mailing lists as part of their investigations. They have honed in on a rogue, right-wing element of the party with Canberra connections.

Meanwhile, campaigning at Viewbank College with Mr Andrews was local Labor MP Anthony Carbines, who was asked about Mr Andrews' handling of the situation. Mr Carbines said he was pleased the leader had committed to upgrading the school.