He had been travelling at 149km/h in a 50km/h zone in Albany, on Auckland's North Shore.
In the residency form, Dotcom signed in June 2010, there is a clear tick in the box declaring no dangerous driving conviction.
The Herald obtained details of the conviction from the North Shore District Court, where it was recorded under the name "Kim Schmitz", the identity under which Dotcom was born.
Kim Dotcom's residency application (App users click here)
Kim Dotcom's residence special direction (App users click here)
The Immigration NZ statement said the agency would check with police to "confirm if there are any undeclared convictions relating to Mr Dotcom.
"If any adverse information is obtained, INZ will assess if there is any liability for deportation. Any such assessment could take several months to complete."
In a written statement, Immigration NZ admitted it had no idea Dotcom had a conviction for dangerous driving until it was told by the Herald.
The statement said Immigration NZ didn't know because it never did a police check.
The statement read: "Immigration New Zealand (INZ) can confirm that Kim Dotcom did not declare a dangerous driving conviction in New Zealand.
"Normally there is no requirement for a New Zealand Police check if an applicant has lived in New Zealand for less than 12 months at the time their residence application is lodged and there are no reasonable grounds to suspect the applicant has been charged with an offence in New Zealand."
The statement said it did not check because "Mr Dotcom did not declare any convictions in New Zealand and had been living here for less than 12 months".
The undisclosed conviction is the latest in a string of decisions by Immigration NZ which have raised questions over the handling of Dotcom's residency application.
The Heraldrevealed this year Dotcom was given residency after the SIS raised a red flag over the FBI investigation. Staff at the intelligence agency later referred to "political pressure" being behind the residency application being granted - a claim the Government has denied.
Then, a month after Dotcom was granted residency, his lawyers revealed previously undisclosed share trading charges in Hong Kong. Immigration NZ staff considered deportation at the time but upheld Dotcom's residency.
Former Immigration Minister Jonathan Coleman was informed throughout the process.
Immigration NZ would initially not comment on the discovery of the dangerous driving conviction, citing Dotcom's right to "privacy".
But the statement today came after the Herald pointed to a decision by Immigration NZ to release Dotcom's entire residency file in March 2012.
At the time, Immigration NZ said it was releasing the entire file to assure the public it had acted properly in granting residency.
Immigration NZ's then-acting chief executive, Steve Stuart, said staff were "meticulous" in the checks made to grant the tycoon residency.
Mr Stuart said release of the residency file would show "the public ... how thoroughly we considered his application and that all factors were taken into account before residence was granted.
"The review found that the correct procedures and processes were indeed followed."
Dotcom and three others are facing an extradition hearing in February next year in response to charges of criminal copyright violation from the United States.
Dotcom timeline
September 10, 2009: Kim Dotcom is pulled over doing 149km/hr in a 50km/hr zone in Albany, on Auckland's North Shore.
September 14, 2009: Dotcom pleads guilty to dangerous driving through a letter presented by his lawyer to the North Shore District Court.
June 3, 2010: Dotcom signs his residency application, revealing two convictions wiped under Germany's clean slate law. He ticks "no" to having a "dangerous driving conviction".
November 1, 2010: Dotcom has residency granted for himself and his family.
December 15, 2010: Dotcom arrives in New Zealand for the first time as a resident.
January 20, 2012: Police raid the Dotcom mansion, arresting the tycoon and three others on FBI charges of criminal copyright violation.
February 2015: The extradition hearing on the charges is scheduled to be heard.
