NZME and Stuff - the new name for Fairfax Media's New Zealand business - is in a last-ditch fight for merger approval with an appeal against the High Court's refusal.

NZME says their case will focus on the court's assessment of the deal's impact on media plurality. The court backed the May decision of the NZ Commerce Commission to block the deal. Fairfax is also challenging the court's decision.

In May last year, NZCC said the merger would concentrate media ownership and influence "to an unprecedented extent for a well-established modern liberal democracy" and the High Court upheld the decision in December.

"After careful review and analysis of the High Court's reasons, the companies continue to believe that the NZCC was wrong in fact and wrong in law to decline clearance or authorisation of the merger," NZME says in a statement. "The findings of the High Court revealed that the NZCC had significantly understated the quantifiable public benefits from the proposed merger."