The Victorian Liberals have accused the state's electoral commission of politicising its referral of party leader Matthew Guy to the corruption watchdog.
The commission has sent its probe into Mr Guy and his former chief of staff Mitch Catlin to the Independent Broad-based Anti-Corruption Commission for further investigation.
Mr Catlin resigned in August after it was revealed he solicited a billionaire Liberal donor to make more than $100,000 in payments to his private marketing company.
Since Wednesday's referral, Mr Guy has repeatedly said he and his party have fully co-operated with the electoral commission and denied exploiting a legal loophole to stymie the probe.
But the VEC has publicly contradicted that claim, declaring it has not received full co-operation from those involved.
"All the key players in that initial issue were invited to respond to questions," VEC spokeswoman Sue Lang told Melbourne radio 3AW on Friday.
"We received no satisfactory response from anybody."
In Werribee to announce plans to establish a special economic zone in the area, Mr Guy said he had handed over all requested material to lawyers but has had no direct contact with the VEC.
"I have totally complied to the full extent of the law and I will to anyone else that asks," he told reporters.
"I've done nothing wrong. This is the first I've heard to the contrary."
Asked if he was lying, Mr Guy said: "I don't accept that whatsoever. That's not the case."
Mr Guy denied suggesting the commission was lying but said it was "fair" to question whether the body should be making statements on the matter eight days out from election day.
Liberal state director Sam McQuestin has since instructed the party's lawyers to write to the electoral commissioner, accusing the VEC of "serious, deliberate and unprecedented interference" in the election.
It has requested the VEC refrain from any further public commentary on the case until after the election campaign, immediately stand down Ms Lang and initiate an external and independent review of its conduct.
In a response, Electoral Commissioner Warwick Gately said "the VEC does not change its regulatory approach as election day nears".
Labor minister Danny Pearson branded the Liberal's intervention an unprecedented attack on the VEC's independence and integrity.
"The VEC has a job to do. They weren't getting the answers that were needed ... so that's why they have referred this matter on to IBAC," he said.
Mr Guy said IBAC was yet to approach him or the party's lawyers and wouldn't be drawn on whether he would stand down as leader if it confirms launching a probe.
An IBAC spokesperson declined to comment on the referral, citing policy.
The stoush comes with Premier Daniel Andrews again refusing to commit to reforming Victoria's upper house voting system before a review of the November 26 poll.
A covertly recorded video showing so-called "preference whisperer" Glenn Druery discussing manipulating the upper house group voting ticket system was leaked by the Angry Victorians Party and published this week.
A Labor-chaired committee in 2020 recommended an inquiry into group voting tickets after the 2018 election but it has not materialised.
The coalition has promised a system overhaul if elected but Mr Andrews declined to match the commitment, wanting to wait for the verdict from parliament's post-election committee.
The Labor leader confirmed his chief of staff met with Mr Druery when he worked as an advisor to the Justice Party but insists it was about staff resources.