"The worker suffered wounds to his head and arm, and was treated by Magen David Adom," NTA said in a statement. "Police have started searching for the perpetrator."
Construction work on the Light Rail's Red Line, due to commence operations in 2021, led to the closure of Jaffa's Jerusalem Boulevard in late May.
Once complete, the 24-kilometer Red Line will connect Tel Aviv to the nearby towns of Petah Tikva, Bnei Brak, Ramat Gan, Jaffa and Bat Yam.