Former prime minister Julia Gillard has stressed that the landmark National Disability Insurance Scheme was not intended to replace the mental health system.
The program, which was introduced under her Labor government more than five years ago, was right to also support people with psychosocial disabilities, she told a forum in Melbourne on Wednesday.
Critics, including clinician and former Australian of the Year Patrick McGorry, have previously questioned whether the scheme could cope with mental illness and said the eligibility criteria was poorly defined.
Changes to NDIS were announced earlier this month in a bid to better support those with severe mental health issues, such as depression and schizophrenia.
Ms Gillard said she was "immensely proud" of what the scheme represents in a keynote address at an NDIS forum, describing it as "big and nation-changing".
"But let's be clear what the NDIS is not," she said.
"The NDIS was never intended to replace the mental health system.
"Some have contended that including psychosocial disability in the NDIS was a mistake. I don't believe it was."
Ms Gillard said if it had not been included, there would still be talk of issues surrounding the scheme's implementation and campaigners would be pushing for mental health to be addressed.
"The real issue here isn't revisiting what the NDIS is meant to cover but taking the time and showing the flexibility, transparency and co-operation necessary to get it right," she said.
Ms Gillard said she understood the frustrations of families "who feel pushed and pulled around" during the implementation phase but is confident solutions will be found.
"Great reform takes time to grow deep roots," she added.
Ms Gillard, who is now chairwoman of BeyondBlue, spoke on the first day of the Mental Health Victoria and Community Mental Health Australia conference in Melbourne.
Her speech came a week after Victorian Labor pledged a royal commission into mental health if re-elected on November 24.
