Jacinta Allan took the extraordinary step in a letter sent to the state secretary of the Victorian Labor Party on Monday morning.
It comes following reports factional powerbrokers agreed Ms Allan had lost the support of the caucus at a meeting on Sunday.
Ms Allan addressed those reports in the letter, obtained by AAP, to party secretary Nick Staikos on Monday.
"I refer to media speculation regarding the leadership of the State Parliamentary Labor Party," she wrote.
Ms Allan requested the state secretary provide support for a ballot of eligible party members and announced her intention to stand.
"I also wish to formally notify you of my intention to be a candidate for the leadership of the State Parliamentary Labor Party, in the event that an election is required," she wrote.
Should Ms Allan refuse to resign on Monday, her three-year tenure at the helm of the party could be challenged at a caucus meeting on Tuesday.
It comes just four months out from the state election on November 28, when Labor will vie for a historic fourth term in government.
A leadership challenge could take weeks to resolve and hamstring the state government.
Deputy Premier Ben Carroll, from the party's right faction, is considered the most likely successor.
Whether he has the numbers, or the ambition, to replace Ms Allan, from the party's dominant left faction, is not yet clear ahead of a cabinet meeting on Monday.
Ms Allan stared down previous leadership rumblings in June after poor polling pointed to a likely electoral defeat and her lowly popularity rating.
Mr Carroll publicly ruled out a challenge at the time, throwing his weight behind the premier.
Standing beside Ms Allan, the deputy premier denied he was coming for the premier's job or that he would ask her to stand aside.
"I can look you in the eye and I can say that, premier," he told reporters at the time.
Attorney-General Sonya Kilkenny, a close ally of Ms Allan, shrugged off the leadership speculation as "idle gossip" on Sunday.
"She has my full support, and this idle gossip doesn't help Victorians," she told reporters.
Federal Liberal senator James Paterson, from Victoria, said a change of leadership would not revive the party's chances at the November poll.
"It sounds like the factional bosses have finally caught up with the sentiment of Victorians, which is they want this premier gone," he told ABC's Radio National on Monday.
"But in my view, it's too little, too late."
He said Mr Carroll, as deputy leader, was tarred with the same brush as Ms Allan in the minds of voters and a change of government was needed.
Ms Allan has been under sustained pressure to call a royal commission into alleged corruption on major Big Build infrastructure projects across the state.
The premier has repeatedly ruled out doing so, arguing a more immediate solution was needed and that an inquiry would not lead to cultural change.
The latest Resolve Political Monitor earlier in July found 43 per cent of Victorians wanted the opposition leader to lead the state, against 24 per cent for Ms Allan.
The survey of 1000 Victorians put the primary vote of both major parties neck-and-neck at 27 per cent, compared with 22 per cent for One Nation.
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