A man aged in his 20s admitted the offence and was sent forward for trial by Judge Desmond Zaidan.
Sgt Jim Kelly said it would be claimed that the incident happened in the Ryston area of the town in last February as the adult woman was walking home at 3.55am.
The defendant was leaning against a wall and he said he was feeling unwell. She tried to help him and get a taxi but he attempted to kiss her.
The woman pushed him and he then took her by the waist and pushed her against a wall before penetrating her vagina with his fingers.
Sgt Kelly said it would be further alleged that the defendant was later identified on CCTV.
On hearing that the defendant had been in foster care for most of his life, Judge Desmond Zaidan asked how the State could be held accountable for releasing him at 18 with, apparently, little in the way of follow up care or education.
“There may be an innocent reason for 16 movements through the foster care system but I would like an explanation,” he said.
He also criticised the State for separating siblings at a very young age.
“Nobody is being held accountable or we’ll wait for another tribunal in 50 years,” added Judge Zaidan.
The defendant told the court his mother died when he was very young.
The case was sent to the sitting of Naas Circuit Court sitting, starting on January 20 next.