Nicola Sturgeon has not spoken to her predecessor Alex Salmond since he was charged with a series of sexual assault offences earlier this year, she said.
Salmond pleaded to 14 separate allegations involving 10 women when he appeared at the High Court in Edinburgh last week and said he would "vigorously" defend his position.
The former First Minister faces a charge of attempted rape, 11 charges of sexual assault - including one with intent to rape - and two charges of indecent assault.
He was arrested and charged in January this year.
Nicola Sturgeon said her only interest in the case is to see that justice is done and that this requires due process and a fair trial.
In an interview on ITV Tonight on Friday, the current First Minister was asked when she last spoke to him.
She replied: "I haven't spoken to him since he was charged with these offences."
Asked how difficult she finds the situation, she said: "I haven't spoken to him in some time but he is facing a criminal trial here and it would be really inappropriate for me to make any comment.
"I think my feelings and how difficult it is for me is the least of it in this. There are serious allegations that have been made."
She added: "My only interest in this not just as First Minister but as an ordinary citizen is that justice is done whatever that turns out to be but that requires due process and a fair trial and that's in the interest of those who have made allegations as it is in his interest as well that the truth is established in that trial and that is the most important thing."
A trial date has been set for March 9 next year.
Speaking outside the court after he appeared on November 21, Alex Salmond said: "I am innocent and I will defend my position vigorously but the only place, the only proper place to answer criminal charges, is in this court - and that's exactly what we intend to do next spring."
