Dahlan, a member of Fatah's Central Committee, told reporters in Ramallah that "due to the nature of its relations with Iran and Syria, Hamas is finding it difficult to reach a decision and is impeding internal (Palestinian) reconciliation because of foreign interests."
Egypt has been struggling to broker a reconciliation agreement between the two main Palestinian factions for months and this month proposed an agreement that would see new elections held in June.
Fatah has signed the agreement while Hamas has repeatedly postponed its official response, saying it needs more time to mull the deal.
"Hamas has a bigger stock of lies than Netanyahu," Dahlan said during the press conference, referring to Israeli Prime Minister Benjamin Netanyahu.
"They got everything they asked for in the Egyptian document, and we in Fatah knew that our position would draw fire from the sons of Fatah... But despite all this we agreed to it," he said.
Dahlan insisted that in the absence of a deal Palestinian President Mahmoud Abbas, who heads Fatah, would call elections for January in accordance with the constitution.
"We have taken our final decision to go to elections at the constitutionally appointed time... because we respect the law," he said.