Dotcom in happier times. Getty/Jason Oxenham Kim Dotcom has been fighting extradition to the US for five years, but it's a minor driving offence that could be his final undoing.

The famed German internet entrepreneur has spent millions battling the world's biggest copyright infringement lawsuit. But it's failing to declare a dangerous driving conviction for speeding in 2010 when he applied for residency in New Zealand that could force him to leave, Torrent Freak reports.

The online businessman, once owner of the incredibly popular Megaupload site, faces perpetual legal uncertainty until the case is resolved. The US has seized his assets and considers him a fugitive — despite the fact he hasn't been found guilty or, in fact, ever visited the country. He's lost all his money and the situation is hugely complex.

But it's all come down to the simple matter of not telling the authorities in New Zealand about a speeding offence. Now, there's a deportation inquiry into his application for residency. It's worth pointing out here that deportation is different to extradition: It means being forcibly removed from a country, rather than being handed to another country as a criminal.

The driving offence came in 2009. Dotcom was clocked motoring in his 3.6 litre AMG Mercedes at 92mph (149km/h) in a 30mph (50km/h) zone.

AMG Mercedes — a slightly later model from 2012. Flickr/Ben

He was caught by a police radar not far from his mansion in Coatesville, US, and described it at the time as a "stupid mistake." Dotcom is said to have expressed regret over the incident and defended himself by stating that he'd reduced his speed when he became aware of the speed limit. At the time, the judge fined him $500 plus $130 costs and banned him from driving for six months.

Torrent Freak has found that Dotcom put "no" in a response to a question asking: "Have you or any of your family members included in your application, ever been: Convicted of an offence including traffic offences committed within the last five years, involving dangerous driving or driving having consumed excessive alcohol."

In the same immigration records, the internet mogul did reveal a hacking conviction from 1994, and a conviction from 2001 for insider trading, for which he was handed a suspended sentence. Both are said to have been dealt with through his home country of Germany.

The New Zealand Herald reports that the country's immigration minister, Michael Woodhouse, could decide within a month whether Dotcom can stay. The businessman says that the omission was down to a misunderstanding with advisors, but it's still led to the high-level deportation inquiry. It means he could be forced to go to either Germany or Finland — not the US.

It's not clear whether deportation would harm his extradition case. Either way it wouldn't be good for Dotcom to leave New Zealand, where his wife and children live, and where he lives in a massive mansion.

Dotcom tweeted this recently:

Here's the house he'd have to leave behind...