Garrett Dunn, who Wollongong Local Court heard had a history of committing violent crimes, was sentenced to a minimum 12 months' jail for repeatedly punching the young woman while the pair were driving.

Magistrate Michael Stoddart labelled Dunn "an absolute bully".

"No-one deserves to be treated like that," he said.

He sentenced the 24-year-old to an overall jail term of 16 months, with a non-parole period of 12 months.

With time already served, he will be eligible for release in December.