(File photo) Indicted Megaupload founder Kim Dotcom.

Wellington - Internet mogul Kim Dotcom denied on Monday that he hacked a right-wing blogger and leaked emails that have embroiled New Zealand's conservative government in dirty tricks allegations ahead of a general election.

Claims arising from the stolen emails that Prime Minister John Key's government colluded with blogger Cameron Slater to smear political opponents have dominated campaigning ahead of the September 20 election, with Key dismissing any suggestion of wrong-doing.

The emails were originally cited by left-wing author Nicky Hager in his book Dirty Politics, released this month, triggering intense speculation about the source of the documents and how they were obtained.

Slater last week said he believed Dotcom was behind the cyber-theft from his blog “Whale Oil”, an allegation the German national has rejected.

“Let me just be crystal clear, I have nothing to do with the hacking of Whale Oil,” Dotcom told Radio New Zealand on Monday, saying the extent of his involvement with the site was to monitor it for defamatory statements.

“I was going to take legal action against Cameron Slater after he has written 200-plus smear stories (about Dotcom), character assassinations,” he added.

The main thrust of the Whale Oil allegations are that one of Key's former staffers and a senior minister fed sensitive information to Slater, using his blog to damage opponents.

Dotcom, who is fighting a US attempt to extradite him for alleged online piracy, has been an active participant in the New Zealand election, bankrolling the Internet-Mana Party in a bid to prevent Key winning a third term in office.

Dotcom has made no secret of his desire to see Key ousted in the wake of the 2012 raid on his Auckland mansion, when the Megaupload founder was arrested and his online empire crippled.

Opinion polls show the dirty tricks allegations have had a negative impact on the government - although it does not appear to be enough, yet, to tarnish Key's chances of securing another term. - Sapa-AFP