National Party Leader John Key says Labour's latest attempt to link him to the controversial H-Fee is little more than a desperate smear less than a fortnight out from the election.

"This is a desperate attempt by the Labour Party to smear me 10 days out from the election. I have never been involved in the H-free transaction. The Serious Fraud Office Director at the time has confirmed that."

Former SFO head Charles Sturt has previously confirmed: 'Mr Key was simply one in a "vast array of innocent people, potential witnesses, in a massive fact-gathering exercise. I feel compelled to fully support the reported comments of John Key in relation to the H-Fee transaction. It should not need to be said that John Key was completely innocent of any wrongdoing whatsoever. For any politician to hint or suggest otherwise would be absolutely rubbish and pure mischief-making'.

Mr Key says the Labour Party's desperate attempt to link him with this issue again now appears to revolve around an earlier H-Fee transaction which took place in Australia while he was working for Elders in New Zealand.

"I was not involved in, or even aware of, that earlier transaction. Labour is clearly scraping the bottom of the barrel and will stop at no lie or innuendo."

Mr Key says he has previously clarified the year of his departure from Elders in the New Zealand Herald on July 19.

"I remain focussed on the issues that matter to New Zealanders. I challenge Helen Clark to do the same, and face up to her record on law and order, the economy, health and education."