Any changes to the way the GST is carved-up among the states and territories will be rolled out in a way which ensures government funding is not eroded, Treasurer Scott Morrison says.
The Productivity Commission has handed to the federal government its final report into the GST distribution process.
Prime Minister Malcolm Turnbull said the report would be publicly released within weeks, rather than months.
Mr Morrison said there would be a "clear transition plan" to any new system, once his fellow treasurers were consulted in coming weeks.
"If you're going to make any changes, that means all states are in a process to ensure what they're getting currently - the amount of money they're getting currently - is not eroded as well," Mr Morrison told reporters in Townsville on Tuesday.
He said the federal government would not be adopting the usual process for Productivity Commission reports, which involves waiting 25 parliamentary sitting days before responding.
"It's another important next step in this process as we work through trying to make the GST more reliable in terms of the distributions made to the states, and more predictable so states and territories can budget with more certainty," Mr Morrison said.
The interim report said the system - known as horizontal fiscal equalisation - should use the second-strongest state or average as the basis of the carve-up, rather than the strongest.
State and territory treasurers plan to meet in Melbourne next week, without Mr Morrison, to discuss their priorities for reform.
It will be the second meeting of the Board of Treasurers since it was set up late last year.