Treasurer Tim Pallas is understood to have addressed an emotional Labor caucus meeting on Tuesday morning declaring he would "not name names" but the person responsible for leaking sensitive documents should "go".

According to one account, Bentleigh MP Nick Staikos then said he would "not be as kind" as Mr Pallas, naming Jane Garrett as the source of the leak and reiterating the demand that she resign.

In a bitter reprisal, a number of MPs, some of whom were in tears, also spoke against Ms Garrett, whose seat of Brunswick is under threat from the Greens, vowing not to support her in any preselection contest or vote.

Senior Labor sources claim to have obtained evidence that Ms Garrett is the source of the leak.

In a curious twist, one of Ms Garrett's electoral officers appears to have inadvertently sent a text message to a Labor insider with the same name as a News Corp journalist. It is understood it is not the first time a text had been mistakenly sent.

The text message, sent yesterday, has been circulated widely among caucus.

Seen by Fairfax Media, it reads, in part, "Mate ... Janes (sic) asked to call you to drop something off".

Others have cautioned the message provides no proof Ms Garrett was the source of the leak, and that major assumptions are being made.

At a marathon caucus meeting on Tuesday, 40 MPs spoke about the need for leaks against the government to stop.

Jane Garrett refused to comment on caucus after the meeting finished at 11.30.

She said she had read "with interest" the story in the morning press.

"It has obviously been a very, very difficult time," Ms Garrett said.

Minister Jacinta Allan said "it was a great caucus meeting", while Treasurer Tim Pallas said the meeting was handled "respectfully."

The explosive development comes as the Premier's former boss warns the Andrews Government is in danger of becoming a "train wreck" amid persistent white-anting and internal leaks.

Recently retired federal MP Alan Griffin, who gave Mr Andrews his first break in politics as an electoral officer, has bluntly warned Labor is in danger of self-destructing.

In an opinion piece for Fairfax Media, Mr Griffin, the former member for the federal seat of Bruce who wrote the well-respected review of state Labor's 2010 election loss, warns the "train wreck" has not yet happened, although "there are worrying signs".

The comments follow the leaking of sensitive documents about Premier Daniel Andrews and the firefighters union, heightening internal tensions and fuelling anxiety that the Government is in danger of imploding.

News Corp reported on Tuesday details of a briefing note from Mr Andrews' industrial relations adviser John-Paul Blandthorn, stating that United Firefighters Union secretary Peter Marshall should  be told to be more respectful to ministers, MPs and staff.

"Marshall has crossed the line in recent months as to what would be considered acceptable behaviour," the leak said.

The memo also said the UFU had looked for government intervention to deliver a result for the union, and that the union was seeking an "unrealistic outcome in both pay and entitlements".

Mr Andrews has previously denied he received any complaints about Mr Marshall's behaviour from Labor MPs.

Mr Griffin said it was clear Labor MPs were deliberately agitating to damage Mr Andrews.

"From bitter personal experience I know what it's like being part of a caucus where this sort of activity is underway," he writes. "Some people become aggrieved, sometimes for good reason, often not, but that's the way it is."

So far any talk of a leadership challenge to Mr Andrews has been brushed off. One report suggest Mr Andrews' detractors had been "counting the numbers" without any obvious challenger identified.

Even so, the industrial dispute between the firefighters union and the CFA over a new workplace agreement for 800 paid firefighters has dogged the Premier, with many Labor MPs baffled at his sudden decision to back Mr Marshall.

For months he backed then-minister Jane Garrett against the union's "outrageous" demands, but following a meeting with Mr Marshall earlier this year he changed tact and backed the union's position.

Since then Ms Garrett and senior CFA officials have resigned and Mr Andrews has sacked the CFA board, forcing a pay deal through. Recriminations are now flowing fast against the people seen as agitators.

On Tuesday, Premier Daniel Andrews said the leaked memo was 12 months old and had been selectively quoted by News Corp.

He said no advice was received that would constitute a complaint. "The memo talks about breaching confidences, leaking stories to newspapers…That is the conduct that is referred to in the memo."

He said a meeting with Mr Marshall had been cordial and ended on good terms.

"The former minister was there. These are silly games," he said.

Mr Andrews said he was not interested in playing "political games".