The National Party president says decisions about who will stand in electorate seats is up to local branches and no pressure has been exerted by the national body.
Colin King, the MP for Kaikoura, has lost his bid to contest the seat in 2014 to new candidate Stuart Smith after being voted out by party delegates.
Radio New Zealand understands there has been some discontent within the local party organisation about Mr King's performance. However, he was reluctant to relinquish the seat, so a challenge was mounted.
It is the first time in more than a decade that a sitting National MP has been successfully challenged. The last time was in 2002 when John Key beat out Brian Neeson for the Helensville candidacy, while Judith Collins defeated Warren Kidd in Clevedon.
Under party rules, every candidate seeking a list place also has to contest an electorate seat, except for five exceptions, who are nominated by the board.
Radio New Zealand has been told that Colin King is unlikely to be among those nominations, so will probably join eight other National MPs who will retire before the next election.
Party president Peter Goodfellow said on Wednesday that no specific message has been given to any of those MPs, as the party is just going through a process of rejuvenation at grassroots level.
Stuart Smith said it was not not easy to challenge a sitting MP, but he believes he has something to offer.
Colin King was elected as MP for Kaikoura in 2005. He won the seat at the last election with an 11,500 majority. Mr King said he supports Mr Smith and is encouraging others to do the same.
Prime Minister John Key said as painful as it is, Mr King's de-selection is part of politics and a healthy process in a party. He said he came into Parliament by challenging the incumbent MP, which he says many National Party supporters would regard as a good thing.
Mr Key said Mr King has been a good MP and he will thank him for his time in Parliament.