Rabah told the Ma'an News Agency Fatah had not yet received written permission from the Hamas-controlled government for the Jan. 1 event. He said Fatah has received verbal assurances.
Fatah was founded in 1965 by Yasser Arafat, who served as president of the Palestinian Authority from 1994 to his death in 2004. The name means conquest in Arabic.
After Hamas won a parliamentary majority in 2006, the party seized control of Gaza. Since 2007, Fatah has effectively controlled the West Bank, while Hamas is in power in Gaza.
Rabah said Hamas leaders and government officials in Gaza would be invited to participate in the Fatah anniversary.