Biswajit Banik and his wife Sarmin Sayeed knew it wasn't easy raising a child with autism, but were happy doing it in Australia after moving from Bangladesh in 2007.

But the Monash University lecturer and his GP wife were devastated when they learned late last year that their dreams of living permanently in Australia would be shattered because of the disability suffered by their son, 12-year-old Arkojeet.

Dr Biswajit Banik and his wife Dr Sarmin Sayeed with their autistic son Arkojeet Banik. Credit:Chris Hopkins

Immigration officials have told Dr Banik his application for permanent residency has been denied, despite nine years in the country, solely because of his son's disability. The family now faces an uncertain future, not knowing if they will be ordered to leave Australia.

"The uncertainty of our future, it is pretty difficult," he said. "Our battle with immigration is overwhelming…It's quite devastating because the whole of our lives we have believed in a fair and equitable society.