Winston Peters says the leaking during the 2017 election campaign of his superannuation overpayment did not influence New Zealand First's coalition choice.
But he said it reinforced National's instinct "to destroy rather than to build."
Peters, now Deputy Prime Minister and Foreign Minister, led the party that held the balance of power after the 2017 election and which eventually tipped National from power to form a minority coalition with Labour, supported by the Greens.
The superannuation overpayment was revealed by Peters himself during the election campaign, after two news media outlets had made inquiries about it.
It has been unproven who leaked the fact that Peters, aged 72, had been overpaid superannuation for six years – although he has pointed the finger at National given that two ministers, Paula Bennett and Anne Tolley, were alerted by chief executives under the no-surprises policy.
Peters is also suing the former ministers and State Services Commissioner over the no surprises policy.
In a book on the 2017 election campaign, Stardust and Substance (Victoria University), Peters says the leaking of his superannuation overpayment breached a fundamental right to privacy.
"It did not influence the eventual coalition choice of New Zealand First, as many have erroneously claimed, but it did reinforce National's instinct to destroy rather than to build.
"Instead of wanting to co-operate with our desire for positive change, National's strategy was designed to extinguish it. It was an example of short-term thinking," he said.
"From at least 12 months prior to the general election, National had choices about how it could have proceeded.
"It's approach revealed much about its idea of cooperation, or the lack of it."
Peters said that after the results were in, the left had achieved a swing of over 6 per cent "so the electoral energy was on that side of politics."
"National's electoral energy was spent."
Peters said choosing National would have been the "tidiest" option for New Zealand First, ending up with a two-party majority coalition.
"We instead chose the harder path – of change and regeneration.
"Change was necessary and it is our responsibility to deliver it. And we will."