The incident follows another assault on a woman walking at Ballymount Park, near Tallaght, three weeks ago.
On that occasion a 27-year-old jogger was assaulted and was lucky to survive. The attacker broke her nose and attempted to strangle her at 11.45am on May 30. The incidents are not connected and gardai have issued a photofit of a man in relation to the Ballymount Park case.
Anybody with information should contact the Garda confidential line on 1800 666 111.