Teina Pora's lawyers will this morning begin their fight to have his compensation payout adjusted for inflation - worth around half a million dollars.

He was paid out more than $2.5 million And given a government apology for being wrongfully convicted of the rape and murder of Susan Burdett.

Mr Pora spent 21 years in prison.

Law professor at Otago University Andrew Geddis told Mike Hosking these wrongful conviction payments are political decisions.

"We do it out of the goodness of our heart, not because we are legally bound to, and that's probably the main problem they're going to face when convincing the court to interfere here."

LISTEN ABOVE AS LAW PROFESSOR ANDREW GEDDIS SPEAKS TO MIKE HOSKING