Western Australia has signed up to the national disability care scheme because the federal government made concessions to suit the state, Premier Colin Barnett says.
WA was the final state to agree to the scheme and will have two trial sites.
Prime Minister Kevin Rudd made the announcement on Sunday after finalising the details with Mr Barnett on Saturday night.
"There are some unique features to the WA scheme but I think it's going to be good for everybody, particularly for those suffering from disabilities," he said.
One of the sites will be a continuation of My Way, which is the WA system that allows people with a disability to select the services they want from mostly not-for-profit organisations.
Mr Barnett said the trial site for My Way would be in the South West region and the Kwinana-Cockburn area.
The Commonwealth's system would be conducted in Midland, the Perth Hills area and adjoining suburbs, he said.
"I think at the end of the day, we will learn something from both sites and it will play an important role in the way in which disability services are ultimately provided right across Australia," Mr Barnett said.
The premier had previously said the NDIS would probably be on hold until after the election, but said he now believed it was important to compare how the two systems worked and how they could be improved to provide the best care.
Mr Barnett said the federal government had made concessions to suit WA because the state did not want a centrally controlled system.
The WA government will fund 60 per cent of the trial, while the federal government will fund 40 per cent.
"We have stuck to our guns as a state and we've got a better result for Western Australia," he said.
The trial will be conducted from 2014/15.
