He stressed the case should be closely managed and another hearing for next month was set down.
At its peak, Dotcom's Mega website was the 13th most popular on the internet, accounting for 4 per cent of all online traffic.
In 2010, it is estimated Dotcom earned US$42 million, Ortmann US$9 million, Van der Kolk US$2 million and Batato US$400,000.
But the Crown said that money was earned through spreading copyright-infringing material around the globe.
Judge Dawson agreed there was an "overwhelming preponderance of evidence" that there was a case for the quartet to answer.
His ruling came after almost four years of legal wrangling following a dramatic police raid on Dotcom's north Auckland mansion in January 2012.
Dozens of police, including New Zealand's elite anti-terrorism police unit, carried out a dawn raid arresting Dotcom, Batato and Ortmann.
The other defendant, Bram van der Kolk, who like Dotcom has permanent residency, was arrested at his upmarket Orakei home.
The FBI warrant sought the four on a range of charges relating to the Megaupload business, from criminal copyright violation through to money laundering and operating an organised criminal conspiracy.
If found guilty in the US, the men could face lengthy jail terms.