A jury convicted the man, who cannot be named for legal reasons, of strangling Grace Millane on her 22nd birthday in December 2018 after they met via Tinder.
Miss Millane went out for drinks with him before returning to his hotel apartment in central Auckland, where he killed her.
He stuffed her body into a suitcase, drove to a forest and buried it in a shallow grave, where police found it a week later.
Prosecutors argued in the trial that the man deliberately strangled Miss Millane to death, while defence lawyers claimed the death was accidental after the pair engaged in consensual erotic choking that went too far.
The jury found the man guilty and a judge sentenced him to life imprisonment with a minimum non-parole period of 17 years.
Lawyer Rachael Reed told the Court of Appeal judges that she was not seeking to excuse the man’s “abhorrent” actions after Miss Millane’s death, according to news organisation Stuff.
But she said the judge placed too much weight on those actions in determining the man’s sentence.
Ms Reed also said the conviction had problems, including questions around the issue of consent, some of the expert evidence, and negative evidence given by other women about the man’s character.
