The Apple co-founder Steve Wozniak has issued a stinging criticism of the new biopic of his fellow computing pioneer, the late Steve Jobs, after a clip from the film was released on the internet before its premiere at the Sundance film festival.

The clip shows actors Ashton Kutcher (as Jobs) and Josh Gad (as Wozniak) discussing the merits of the computer operating system Wozniak has just developed. Jobs is seen trying to inspire a sceptical Wozniak as to the potential future impact of home computers, before the Wozniak character shouts: "Nobody wants to buy a computer. Nobody!"

However, Wozniak, 62, in a series of messages posted on the Gizmodo website where the clip first played, said the portrayal was "not close". "We never had such interaction," he wrote. Denying the accuracy of the scene he also stated: "I'm not even sure what it's getting at ... personalities are very wrong."

Wozniak, who is known in the tech community as "Woz", also implied that far from Jobs being the inspirational leader, at that time it was far more probable that Jobs was learning from Wozniak about the possibilities of personal computing.

His idea was to make a $20 PC board and sell it for $40 to help people at the club build the computer I'd given away. He always saw a way to make a quick buck off my designs."

Wozniak continued: "I never looked like a professional. We were both kids. Our relationship was so different than what was portrayed. I'm embarrassed but if the movie is fun and entertaining, all the better. Anyone who reads my book iWoz can get a clearer picture."

• jOBS, directed by Joshua Michael Stern, is due to be released in the US on 19 April but does not have a UK release date yet.