Merry Christmas Kim Dotcom, you could be in jail on December 25.

The Courts of New Zealand website has just forecast that a decision is coming tomorrow in the Megaupload extradition case.

It said through its Twitter account that the "USA v Dotcom & Ors decision will be delivered" tomorrow afternoon by district court judge Nevin Dawson.

The decision comes after a two-month hearing in which the United States applied to have Dotcom and three others arrested in New Zealand in 2012 extradited to face criminal copyright and related charges.

Dotcom, Mathias Ortmann, Bram van der Kolk and Finn Batato have strenuously denied the charges, which were connected to the Megaupload filesharing business operating out of Hong Kong. The business was one of the most popular on the internet, and carried popular movies and music.

Judge Dawson's decision will reveal whether he considers the required level of evidence has been produced to show there is a case for the men to answer in the US.

The next stage is for Justice Minister Amy Adam to decide whether the extradition will go ahead.

If the decision goes against Dotcom and his co-accused, it will likely trigger a fresh bail application as their status will have changed. The four have been on bail since March 2012, and spent the weeks after their arrest in jail.

The Crown, acting for the US, unsuccessfully challenged Dotcom's bail a year ago.

Of the four men, three have families with young children. Dotcom has five children, Batato has two and van der Kolk has one.