The Herald Sun newspaper has obtained audio recordings and documents that it says shows Tristan Weston was paid $22,500 by the Liberal Party.
The payments were allegedly made after Mr Weston was forced to resign as an adviser to Police Minister Peter Ryan in the fallout from the crisis.
The recordings also allegedly reveal Premier Ted Baillieu's chief-of-staff, Tony Nutt, promised to help Mr Weston find another job after he was dumped as Mr Ryan's adviser.
Opposition spokeswoman Jacinta Allan says the recordings appear to contradict the Premier's claim that his office was not helping Mr Weston.
"These revelations show that these matters were being dealt with by the most senior person in his office," she said.
"They involve very senior members of his Government, including the Deputy Premier, and it is quite unbelievable to think that the Premier didn't know that there was something going on."
Jill Hennessy, Opposition spokeswoman for corrections, crime prevention and anti-corruption, went further.
"Victorians deserve to have a government that tells the truth and takes responsibility for its actions," she said.
"We deserve to have a police minister who tells the truth, and we deserve to have a premier that comes clean with the people of Victoria, to explain what in fact occurred in this whole sorry affair."
She says it is not good enough to sweep potential corruption under the carpet.
"We don't want to become the moonlight state as we saw from the horrific history of the Fitzgerald inquiry in Queensland," she said
"They (the tapes) are incredibly powerful of what they reveal, because they reveal the culture of a cover-up that goes right up to the Premier's chief-of-staff.
"It is no mistake that we do not have the Premier out this morning.
"We've got not one member of the Government prepared to step up and defend themselves."
She says the recordings show the Government deliberately defined the anti-corruption jurisdiction to try to make sure these sort of investigations are not included.
"The Government did not include misconduct in public office as one of the offences," she said.
"It is an absolute blight on IBAC's (the Independent Broad-based Anti-Corruption Commission) jurisdiction and it will inhibit their ability to actually investigate this matter."
'Outraged by slurs'
Michael Strong, a former judge of 20 years who headed the OPI, says he is outraged by what he says is a "totally gratuitous slur" against his staff by some of the remarks heard in the tapes.
Mr Strong says Mr Nutt appears to be alleging the OPI was corrupt and "fitted people up".
"What that means is that, allegedly, we made allegations and findings against people, knowing those allegations and findings were false.
"That I assume is the basis of the allegation that the OPI under my leadership was corrupt.
"Now that is all outrageous.
"It is an outrageous slur, after many, many years of public service, 20 years as a judge, and a terrible slur on my very dedicated staff.
"I have no problem with anybody investigating the OPI, I have nothing to hide.
"Me and my staff acted with complete integrity."
In another recording, OPI staff are described as third-rate staff and the biggest bullies in town.
"It's a totally gratuitous slur," Mr Strong said.
"They (his former staff) are some of the finest people I have ever worked with."
He also raised concerns about the future of his former staff saying the recordings appear to reveal Mr Nutt's plan to ensure OPI staffers did not work in the new anti-corruption regime.
"Now the Minister, Mr Andrew McIntosh, has repeatedly said that the staffing of IBAC would be entirely a matter for the new commissioner, and I told the staff the same thing, relying on Mr McIntosh's assurances.
"It now seems there's been a plan afoot for a very long time from within the Premier's office to get rid of a lot of them, and I find that disturbing."