Apple co-founder Steve Wozniak has praised actor Michael Fassbender for his uncanny portrayal of Steve Jobs in Universal's upcoming biopic about the iconic businessman.

Fassbender, 38, will play the late Apple CEO in Danny Boyle's Steve Jobs, one of two films being released about the tech icon later this year.

Wozniak - who co-founded Apple Inc with Jobs in a Californian garage in 1976 - said the Irish actor's portrayal of Jobs was the most authentic so far.

"I saw a rough cut and I felt like I was actually watching Steve Jobs and the others...not actors playing them," Wozniak told Deadline Hollywood.

"I give full credit to Danny Boyle and Aaron Sorkin for getting it so right."

The support from one of Jobs' closest confidants is expected to be a win for the feature which has already received critical praise following its worldwide premiere over the weekend.

Variety praised Fassbender for an "enthralling" performance and dubbed Steve Jobs a "brilliant, infuriating and richly unconventional take on the life of an American visionary".

The blockbuster written by The Newsroom's Aaron Sorkin features an all-star cast, with Seth Rogen playing Wozniak, Jeff Daniels starring as John Sculley, Apple's former CEO, and Kate Winslet playing Joanna Hoffman, an original member of the Mac team.

Fassbender's performance is expected to earn him several Oscar nominations.

Steve Jobs is based on the 2011 best-selling biography by Walter Isaacson and will compete with documentary Steve Jobs: The Man In The Machine in theatres this Spring.

Directed by Oscar-winning documentary maker Alex Gibney (The Armstrong Lie), Steve Jobs: The Man In The Machine uses archival footage and interviews to paint an unflattering picture of Jobs as demanding and ruthless.

Ashton Kutcher was the first actor to play the man synonymous with the world's largest tech company in 2013 film Jobs.

The movie bombed at the US box office, only taking $16 million, and was given a paltry review of 27 per cent on Rotten Tomatoes.

Steve Jobs will be released in American cinemas on October 9.