The comments by Gaza's Mahmoud Zahar were carried by the Lebanese newspaper al-Akhbar on Tuesday. They signal a rare public dispute among Hamas leaders.
Zahar said the group's exiled leader, Khaled Mashaal, had no right to say that Hamas would give Palestinian President Mahmoud Abbas another chance to try to negotiate a peace deal with Israel.
Zahar was also quoted as saying that the Hamas power structure should be reassessed.
A confidant of Mashaal responded that Zahar spoke out of turn.
Zahar was not available for further comment. A Hamas spokesman in Gaza said the published statements were fabricated.