Suheel al-Jadeli, 39, was detained aged 17 and sentenced to 22 years by an Israeli military court. He was accused of involvement in the killing of an Israeli soldier in al-Bureij refugee camp in the Gaza Strip during the first intifada, said Abed al-Nasser Farawneh.
Al-Jadeli, who is from al-Bureij camp, has served his full sentence.
Farawneh said there were 27 prisoners from Gaza in Israeli jails who were detained before the 1993 Oslo accords.
He urged institutions and residents to arrange welcoming events for al-Jadeli on his return to Gaza after more than two decades.