The police handling of the "red shirts" probe has caused ructions among some people involved in the investigation, who have become increasingly concerned about interference from senior figures in force command.
Some officers are troubled about a directive given to detectives, which they consider inappropriate and overly deferential to MPs accused of misusing public funds for political benefit.
The Age can reveal that some officers from the fraud and extortion squad were told that if MPs did present for interviews, they were not to be searched, photographed or have their fingerprints taken.
The instruction appears to be inconsistent with standard police procedure but is also dramatically different to the treatment of 17 Labor staffers, who were raided, arrested and interviewed in August.
There is also frustration among some police at the refusal by Labor MPs and their lawyer Rob Stary to submit to formal interviews.
On Wednesday, Premier Daniel Andrews told reporters the matter would not affect Labor’s chances of winning the November election.
Mr Andrews deflected a barrage of questions on the MPs’ conduct but insisted he had not instructed them to refuse to co-operate with the investigation.
“Much as I might like to answer some of those questions I don’t think it’s appropriate for me to be doing that,” he said.
“I will leave it to Victoria Police to provide comment to you and anyone else they think is appropriate in relation to the work they’re doing.”
Asked why he said in July that MPs would co-operate with police, Mr Andrews said: “I was asked a question, I answered the question.”
Despite the change in position, Mr Andrews said he stood by all the comments he had made.
“I stand by all my comments I make over time. That’s part of the process.”
Fraud squad detectives have the authority to arrest the MPs, but have been told not to exercise those powers, which has created a stand-off as the force awaits advice from the Office of Public Prosecutions.
When taxpayers paid for 'red shirts' to campaign for Labor in 2014, a four-year saga began which is still dogging the party going into the 2018 elections.
"The Premier on July 28 stated publicly he and others would co-operate with police. That he and others now refuse to do so is an appalling affront to the citizens of Victoria," Mr Glare said.
"If there is nothing to hide then those under investigation should be prepared to be interviewed."