Supreme Court weighs whether sex offender Peter Ellis' appeal can continue after death

New Zealand's highest court is weighing up whether a historic sex offender can appeal his convictions from the grave. 

Peter Ellis died of bladder cancer in September but had been fighting to clear his name for over two decades.

Ellis was convicted of sex offences against seven children at the Christchurch Civic Creche.

That later became six children after one recanted. 

Robert Harrison has represented Ellis since 1993. 

He says whilst his client has died, it's important the case does not.

"It also raises an issue of a systemic issue related to the administration of justice," he says. 

Harrison argues the interviewing techniques employed produced contaminated evidence, a problem he says continues.

"In every case where we have children giving evidence, are we addressing them appropriately?"

But Crown lawyer Una Jagose says posthumous appeals should be rare and meet stringent criteria.

She says this case doesn't meet the threshold.

"When the appellant dies, his interests die too," says Jagose.

She says with Ellis' death there is no jurisdiction for the appeal, though she does acknowledge others have invested interests in the case.

"Mr Ellis' supporters and his family don't overwhelm the interests of the victims, now the most directly affected by the offending and conviction."

Justice Joe Williams asked if the court needed to consider tikanga Māori.

He says ancestors have more reputation to protect, and the death of an appellant is irrelevant.

Both lawyers will now make further submissions before a decision is made.