The Hobart Supreme Court heard on Tuesday that a mediator would be required to help the defence and the prosecution come to a decision over how much money Gay needed to pay back following his 2013 conviction.

Gay was fined $50,000 and banned from running companies for five years after he was convicted of selling $3.1 million in Gunns shares with knowledge outside the public sphere six years ago.

The Commonwealth Director of Public Prosecutions wants Gay to pay a proceeds of crime recovery.

But Gay's defence has argued that he did not profit from selling his shares.

Justice Estcourt said on Tuesday that Gay could pay anywhere between nothing and $600,000.

The court heard previously that Gay dodged a $797,798 loss because he sold his shares at 90¢ rather than 68¢ - the price of the shares when Gunns Ltd ran aground.

Justice Estcourt said the two sides could choose their own mediator to help find a resolution, or a court-appointed mediator could review the case in January at the earliest.

The mediator agreed on by both parties can be from anywhere in Australia and the mediation does not have to take place in Hobart.

Gay has previously stated that he sold his shares after being diagnosed with cancer.