Jamie Saxon to be retried over Milton Road death of German backpacker Dominik Schulze

A Queensland man sentenced to life in prison for fatally stabbing a drunk German backpacker has had his murder conviction overturned on appeal.

Jamie Douglas Saxon, 36, was found guilty in October after he allegedly knifed Dominik Schulze, 30, during a Brisbane road-rage incident two years earlier.

The 30-year-old - who was in Australia on a working holiday - was skylarking on an inner-city road after a night of drinking when the men clashed.

Mr Schulze had his pants down and was waving his genitalia about when he was clipped by a car driven by Saxon's girlfriend, Jessica Wilkes.

Angry at being bowled over, he called Saxon names, was abusive and "clearly wanted to fight", the trial was told.

He also pushed Ms Wilkes and attempted to throw punches which didn't connect because he was so drunk.

Saxon did not deny stabbing Mr Schulze but pleaded not guilty to murder saying he had acted in self-defence.

It was alleged Saxon then took a long, sharp fishing knife from the car and stabbed Mr Schulze up to four times.

His conviction was quashed today and a retrial ordered after the Court of Appeal heard the jury had been misdirected during the trial.

Crown prosecutor Mark Green conceded the jury was given incorrect information about aspects of the self-defence argument, but said it did not matter because the trial judge had made other directions rendering the incorrect information irrelevant.

A full bench of the court disagreed. Saxon will be retried at a date to be fixed.