On Monday, Haniya told a cabinet meeting in Gaza: "We did not conclude the consultations to form the government and we will not announce it before the end of next week."
Haniya said he would hold more talks with Abbas in the next two days, but said more time would be needed after that.
He did not list the sticking points. Other officials have said the two sides have yet to agree on who will take the helm of the interior ministry, in charge of the security forces.
One source said Abbas did not endorse Hamas's candidate for the job, Hamouda Jerwan, a retired general.
The leaders also could not agree on who would be deputy prime minister and whether a Syrian-based Palestinian faction should be allowed to join the government, the sources said.
A final political platform has yet to be drafted, they added.
"The Palestinian people are in desperate need of leaders to solve their daily problems and security"
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Officials hoped to meet a constitutional deadline of March 21, the end of a five-week period allotted for negotiations.
Under the power-sharing agreement, Hamas can nominate 12 cabinet ministers, including three independents, while Fatah can propose eight, including two independents.
Haniya will remain prime minister, while Fatah will be able to fill the post of deputy prime minister.
Security men loyal to the rival factions confronted each other in Gaza after members of Abbas's National Security Forces fired in the air near members of Hamas's Executive Force. No one was hurt.
Abbas's men were seeking the return of what they said was one of their positions which Hamas loyalists had taken over earlier in the day, security sources said.
Forces loyal to Fatah and Hamas had been fighting deadly street battles in Gaza until the Mecca agreement calmed the violence.
But they have pushed ahead with expansion plans despite the agreement to form a unity government, Palestinian and Western officials said.