This is very rare in post Rogernomics Labour. Much more common in National with John Key, Judith Collins and John Carter all entering Parliament by winning the nomination off a sitting MP. Competition is good for the party, if not so much for incumbent MPs.
But in Napier, it seems pretty personal with Nash criticising Fairbrother like so:
“I don’t think Russell has shown the energy to win that back for Labour. It’s not because of his age. It is just that in the five years he has been there he has never shown the energy necessary to win that back.”
“My reaction is if it took five years and an election loss of a safe seat and me coming down to get you gee-ed up, then maybe you should have got gee-d up about five years ago.”