Napier's new MP Stuart Nash maintains he's "Labour to the core" after an email emerged linking him to controversial National Party and Dirty Politics figure Simon Lusk, and a bid to start a new political party.
The email obtained by 3News was to Mr Nash from his campaign manager Rob Johnson about 18 months ago.
Mr Johnson said in the email: "You had two friends of yours commission a report from Simon Lusk to the tune of 10 grand as to whether you could gain more influence by establishing your own political party in competition with Labour, or whether you should just essentially buy-off your colleagues".
He warned Mr Nash that working with "enemy strategist" Mr Lusk - who was alleged in Nicky Hager's book to be involved in a campaign to promote far right candidates within the National Party - "showed a lack of strategy, naivet and poor judgment".
"If Lusk's involvement gets back to certain members of Labour Caucus, or NZ Council then your entire campaign and career could be torpedoed," Mr Johnson warned, adding that "Lusk now has leverage over you - for several reasons - indefinitely".