Milner dubbed the "Black Widow", was convicted of the murder of her second husband Phil Nisbet by poisoning him with crushed sedatives in his food in 2009.
She was sentenced to life in prison in 2014 with a minimum non-parole period of 17 years.
Nisbet's death was originally ruled a suicide, but Coroner Sue Johnson raised suspicions which then led to police reviewing the case and ultimately launching a homicide investigation.
Milner (55) has so far unsuccessfully appealed against her murder conviction.
The body samples are held by the Institute of Environmental Science and Research (ESR).
Milner hopes the test results may support an application to the Governor-General for an exercise of the royal prerogative of mercy, which provides a special avenue for criminal cases to be reopened "where a person may have been wrongly convicted or sentenced".
