New Zealand First leader Winston Peters has released an email leaked to him which suggests that National was considering hiring American strategists to help the party with its 2005 election campaign.
Peters has threatened for months to release documents which would be damaging to National.
The email tabled in parliament on Tuesday is from National's leader Don Brash to his party's strategists asking whether they should recruit two Republican campaigners to help National. Brash notes that they would be expensive, but says they were recommended by the American billionaire Julian Robertson.
"It's important that New Zealanders know that elections in this country are run straight up and down, not with secret funding and covert activity," says Peters.
National's leader has reacted with outrage to the latest allegations. Brash says two Americans worked on the campaign, sending out leaflets, but they were not the people referred to in the email and did not determine strategy or policy.
Peters says Brash's explanation does not wash.
He says he does not believe two Americans came all the way to this country to distribute pamphlets around the street.
"That's what party workers at the electorate and branch level do. You don't bring in people from overseas to do that job unless they were writing the pamphlet," says Peters.
It is not the first time Julian Robertson, known for developing the exclusive Kauri Cliffs golfing resort, has been connected to National.
Last July Cabinet Minister Trevor Mallard accused National of having American financial backing.
Brash said at the time that he knew Robertson but that he had no role in National's policies and that he did not know if Robertson had donated funds to the party.
"If Trevor Mallard has any proof about our policies being driven by the United States he should front up and prove it - he can't because it's a lie," Brash said at the time.
Mallard says it is Brash who is now shown to be the liar.
"What is wrong is lying and saying that you don't have involvement when you do," he says.
Of late National has been busy putting the heat on Labour over its budget leaks. But now the tables have been turned and Peters says it is not yet over for Brash.
"He better tell the public exactly what happened because there
are other emails as well," says Peters.