The ousted operator of medical labs in Auckland is to ask the Supreme Court to rule on who should have the $560 million contract.
The Court of Appeal in September took the contract away from DML and returned it to Lab Tests, now owned by Healthscope.
In doing so, the Appeal Court overturned an earlier High Court decision, which was based on a conflict of interest and consultation issues during the awarding of the contract by three district health boards in Auckland.
Thursday is the deadline for DML to seek a further appeal and chief executive Arthur Morris confirms it will do so.
DML has another month to file formal submissions and does not expect to learn until late December or January whether the court will take the case.
In the meantime, the district health boards in Auckland say they will move the contract to Healthscope over the next nine months.
Radio New Zealand's health correspondent says it is still possible that DML may try to prevent that going ahead by seeking a legal stay on the transfer process.