Jatinder Panesar was jailed for six years over the crash at Mooroopna, north of Melbourne, in June 2017.

He was driving passengers when he failed to give way at an intersection and crashed into the minibus carrying nursing home residents.

The 39-year-old blamed undiagnosed sleep apnoea as the cause of the crash.

A jury found him guilty of dangerous driving causing death and serious injury in 2018, but the Court of Appeal quashed the convictions on Friday.

Mr Panesar was not speeding or distracted and had not used alcohol or drugs at the time of the crash.

His lawyers argued at the time because of his undiagnosed sleep condition the jury could not find him guilty because he may have been suffering from a micro-sleep.

"We are satisfied that there was a reasonable possibility, on the evidence, that the applicant's conduct at the time of the offending was not conscious and voluntary," Court of Appeal justices Mark Weinberg, Philip Priest and Stephen Kaye ruled.

They said a jury was not properly instructed and could "not beyond a reasonable doubt" find his conduct was conscious or voluntary.

The County Court judge had also made a "substantial miscarriage of justice" when he rejected a submission to direct jurors that it could not convict unless it could dismiss his undiagnosed sleep disorder was not conscious and voluntary.

Crash victims Valerie McCubbin, 80, Doreen Emmanuelli, 95, and Theresa Tyndall, 91 were returning to their nursing home on the bus after a daytrip.

Mr Panesar will be released from prison immediately.

Australian Associated Press