Peter Jackson is grateful for the exoneration of Making a Murderer's Brendan Dassey

Sir Peter Jackson and Making A Murderer's Steven Avery, now aged 53. Photo (right) / AP

Kiwi director Sir Peter Jackson has voiced his support over a judge's decision to exonerate Brendan Dassey who was one of the subjects of the Making a Murder documentary.

Jackson yesterday posted on Facebook that he had woken to "some great news".

On Saturday, news broke that US District Court in Milwaukee, Wisconsin, overturned the conviction of Dassey who was found guilty of helping his uncle kill Teresa Halbach, a case profiled in the Netflix documentary Making a Murderer.

The judge ordered Dassey freed within 90 days unless the case is appealed.

In January, after binge-watching the 10-part Netflix series over the Christmas holidays, Jackson took to Facebook to say he believed Dassey was innocent.

"It's only by watching the 10 hours of riveting documentary that you will really understand how faulty the US justice system currently is, and how badly it needs fixing," wrote Jackson.

Jackson said the similarities between Avery's case and that of the West Memphis trio, which he co-produced a 2012 movie about, were eerie.

He believes police coerced Dassey, who was aged only 16 at the time, into making a false confession.

Yesterday Jackson thanked everyone for their support and donations to Dassey's cause.

"Fingers crossed that we're heading towards a happy ending."