Background: Migration has been found to be a risk factor for schizophrenia in several high-income countries. Aim: To examine whether overseas migrants to New South Wales (NSW) have higher rates of admission to psychiatric hospitals for psychotic disorders, including schizophrenia and mania, compared to people born in Australia. Methods: The country of birth of people admitted to public mental health units for the treatment of psychotic illness and for non-psychotic disorders between 2001 and 2010 was compared to the country of birth for the NSW population in the 2006 census. Meta-analysis was used to estimate the odds of being admitted for any psychotic disorder, for a schizophrenia-related psychosis and for mania compared to non-psychotic disorder, for those born in Australia, New Zealand and for nine global regions. Results: Those born in Oceania (including Melanesia, Fiji, Samoa, Tonga and other Polynesian islands, but excluding Hawaii and New Zealand) had the highest odds of admission for the treatment of psychosis compared to a non-psychotic disorder and had the highest odds of being admitted with a diagnosis of schizophrenia or mania. Conclusions: In the years 2001-2010, those born in Oceania were at an increased risk of admission to NSW psychiatric hospitals for the treatment of psychotic illness.