A parliamentary inquiry was due to hand down its report on June 16, before its deadline was moved forward by three days.
The report isn't expected to be published until June 23.
Labor is trying to land a deal with the Greens, which would extend the inquiry into the proposed reform in exchange for the minor party's support for the government's tax changes announced in the federal budget.
Under changes to the $56 billion NDIS, the government would kick 160,000 people off the scheme to rein in spending.
Disability Advocacy Network Australia chief executive Emma Bennison said the delay demonstrated politicians were taking seriously the evidence from the more than 4000 submissions.
"That is a positive sign and it is very clear the time frame for the inquiry was not sufficient and it needed to be longer," she told AAP.
"No one is suggesting reform isn't necessary, but it has to be done with disabled people, and not to us.
"We must be listened to properly and not brushed off."
Ms Bennison said the bill needed significant amendments to protect the rights of disabled people, and that the government should co-design reform with disability groups.
Down Syndrome Australia chief executive Darryl Steff said cutting people off support and isolating them from their communities often resulted in their abuse and neglect.
"This cannot become a political football while people with a disability wait for certainty about their future while politicians talk about fiscal savings," he said.
Women With Disabilities Australia chief executive Sophie Cusworth said she hoped the delay meant the extensive evidence is being treated seriously.
"A delay only matters if it is used well," she said.
"The government and parliament must use this time to properly consider the evidence, listen to people with disability, and make sure no reform leaves people without the support they need."
Opposition NDIS spokeswoman Melissa McIntosh said she would welcome a longer inquiry, and called on Labor and the Greens to "stop playing games" on legislation.
"Delaying this report for the second time and having everyone waiting with no transparency about what is going on is only adding to the high anxiety Australians are already feeling about Labor's cuts," she said.
