UPDATE: All Treasurers from the states and territories have voted to remove GST from sanitary products.
State and territory treasurers unanimously backed the change during a meeting with federal Treasurer Josh Frydenberg in Melbourne on Wednesday.
This means the 10 per cent GST impost will be gone in less than three months.
"Millions of Australian women will benefit," Federal Minister for Women Kelly O'Dwyer told Seven Network earlier on Wednesday while discussing the plan.
But the federal government may have a harder time convincing some states and territories to back its plan to change how the GST is carved up.
Treasurers are discussing the planned introduction of a 75 cent floor in GST payments, and the eastern states are concerned they will be worse off.
The plan was hatched to protect Western Australia from its share crashing to the mining boom lows of less than 30 cents in the dollar.
Victorian Labor Treasurer Tim Pallas says the plan's more about fixing a "political problem" for the federal coalition in WA rather than making the distribution of the GST fairer.
"The prime minister claimed that no states will be worse off - but they've provided no mechanism to ensure this is the case," he told AAP.
But Mr Frydenberg said the changes are based on data from the Productivity Commission and will leave all states and territories better off, with Victoria set to get $425 million more under the plan.
"We're putting in an additional $9 billion to support the states and territories," he told Sky.
NSW Treasurer Dominic Perrottet told Sky News he will push for an amendment to the proposal to guarantee states a better deal.
Federal Labor is broadly supportive of the GST changes but is concerned there are no protections for states contained in the government's draft legislation.
But Mr Frydenberg said the government won't put a guarantee into law because it would create "parallel systems".
Prime Minister Scott Morrison is pressuring Labor leader Bill Shorten to back the changes.
EARLIER: Treasurers from across Australia will meet in Melbourne today to discuss GST – and the tampon tax is on the agenda.
Treasurer Josh Frydenberg will be seeking support for a plan which will get rid of the unfair 10 per cent GST on tampons and feminime hygiene products.
"Our federal and state and territory governments have the opportunity to agree to scrap the unfair tampon tax on Wednesday and I would urge them to do so," Greens Senator Larissa Waters said.
The government has previously promised to add tampons to the list of GST exempt items which already includes condoms and food.