Ambrose, who recorded Mr Key's now infamous chat over the teacups with former Act Leader John Banks ahead of the 2011 election, is suing Mr Key for $1.2 million for alleged defamatory comments made by the Prime Minister about him on three separate occasions, Radio New Zealand reported this morning.
Ambrose has now filed papers at the High Court at Auckland.
This morning Mr Key said: "Look I don't resile from anything I've said."
"It's been a longstanding dispute and in the end it'll go through the court process."
Mr Key lodged a complaint with the police who - following an investigation - issued a warning to Ambrose over the recording which Ambrose maintains was not deliberate.
The investigation saw the offices of media organisations searched by police and the content of Mr Key and Mr Banks' conversation widely discussed.
Today, Mr Key brushed of the significance of Ambrose's legal action.
"It's not coming back to haunt me, it is what it is. I have no intentions of settling and absolutely no intentions of resiling from anything I've said."
