Serial offender Arthur Taylor was back at the Auckland High Court on Thursday fighting a prison ban on smoking.
Late last year, the court ruled that the Department of Corrections' ban was unlawful and invalid.
But the department says new regulations brought in a month before that ruling supersedes it.
Taylor arrived in court on Thursday flanked by four guards with his lengthy paperwork stacked in a cardboard box.
He is representing himself, but lawyer Gillian Coombe has been assigned to assist the court.
Justice Brewer began by questioning whether Taylor's argument was moot, as given the recent changes to legislation there is now no issue to be decided and the ban can't be lifted.
But Ms Coombe said the case still needs to be heard as there are significant consequences for potentially hundreds of prisoners.
Ms Coombe said as the new tightened regulations were only validated in February this year, any prisoners disciplined for having or smoking tobacco before that could have the right to seek compensation.