A prominent Indigenous artist found guilty of sexually abusing a 12-year-old girl, who then fell pregnant, has won the right to a retrial.

In 2012, an ACT Supreme Court jury found Dennis Michael Nona, 40, guilty of four counts of sexual assault on two young sisters during the 1990s.

But Nona immediately appealed, on the grounds that the trial judge had failed in a number of ways to properly direct the jury.

The Court of Appeal agreed, finding the jury had been given inadequate instructions, specifically in regard to three significant issues in the trial.

The overturning of Nona’s conviction was not unanimous though, with the former Chief Justice Terence Higgins electing to dismiss the appeal in its entirety.

It is expected Nona’s retrial will be scheduled for later next year.