A dataset showing the number of people who have private health insurance by locality (suburb or LGA or SA2/3). This could be sourced from tax returns filed with the ATO or from the private health insurance regulator. Data relating to the number of PHI holders would ensure de-identification before release.
This information is held by the PHI industry body (Private Healthcare Australia) but it is only disclosed to health insurers.
This information would be useful for private healthcare service delivery planning, which should increase overall efficiency in healthcare delivery.
Also, in the spirit of open data and given that PHI is effectively government mandated and subsidised, information in relation to it should be available as long as it is de-identified.