Her latest bid in the Court of Appeal today, is an attempt to secure the release of Christchurch truck driver Nisbet's hair, blood, urine, and liver samples, which she says will prove her innocence.
This is after the Court of Appeal earlier said it had no jurisdiction over the samples.
However, in a High Court judgment released in July, Justice David Gendall ruled the Court of Appeal does, in fact, have "custody" of the samples and must now decide whether they are to be released to Milner's lawyers.
The 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".
Fergus Sinclair, for the Crown, said he did not oppose the release of the samples but argued the jurisdiction to make that decision rested with the High Court as it was the trial court and therefore the central custodian.
Nikki Pender, acting for Nisbet's sister Lee-Anne Cartier as an interested party in the case, said any new toxicology results would not be able to challenge tests done at the time.
She argued none of the tests being proposed would change the jury's finding of murderous intent.
"What we're dealing with here is Ms Milner attempting to discard one card, but she's still got to play the others."
Milner's lawyer Rupert Glover said it was essential the court understood the application was "only" to obtain samples for testing.
He accepted it was possible the tests would not support the application to the Governor-General.
Glover was in contact with an Australian pathologist after North American doctors cast some doubt over the death.
The pathologist wanted to see the results and would not request that irresponsibly, he said.
"I think he ought to be allowed to do that."
