Scott Morrison has warned the states must be "one in, all in" for a royal commission into the abuse of people with a disability to have any credibility.
The prime minister told a meeting of coalition MPs on Tuesday he would work with the states and territories to bring about the royal commission, but they all had to be on board.
"For it to be a meaningful process then it must learn the lessons of the failings of delivery at the state level," he said.
"That means we cannot give any one state a leave pass - it must be one in, all in."
He said this was consistent with the draft terms of reference Greens senator Jordon Steele-John, a strong advocate for the inquiry, had given him.
Mr Morrison also said Labor's suggestions of a $26 million price tag of any royal commission was not realistic if it was to cover everything from remote indigenous service delivery through to disability provision in education.
The government intends to focus on the delivery of services, an area the commonwealth has historically left to the states and territories.
On Monday in the House of Representatives, Mr Morrison personally moved a motion - which passed the Senate last week despite the government's opposition - backing the royal commission.
Labor, the Greens and disability groups say that unanimous vote is a good first step.
But Labor leader Bill Shorten says it can't be left as a "token vote" and the government needs to now set up the inquiry.
Attorney-General Christian Porter has indicated he believes the government may need Letters Patent - a special legal instrument - from the states in order to hold the royal commission.
Mr Shorten says a timeline is needed, as the idea had been on the books for too long already.
Senator Steele-John said he had asked Mr Morrison for a timeline and the prime minister had told him: "I've said what I said."
"Not a good start," Senator Steele-John said.
