The announcement from Abbas follows months of negotiations and previous violence between members of his Fatah Party and Hamas. Both sides hope the move will put an end to fighting and to international sanctions that have crippled the Palestinian economy.
"The continuous efforts to form a national unity government have ended successfully with the announcement of a political program for this government," Abbas told the media. "Efforts in the next few days will continue to complete the formation of the national unity government."
An aide to Abbas said he expected the president to dissolve the current government within 48 hours.
Hamas swept to power in January in the first Palestinian parliamentary election in a decade. Western nations, including the United States and members of the European Union, and Israel soon after imposed millions of dollars in sanctions on the new government citing its failure to recognize Israel, disarm and adhere to peace agreements.
The lack of funds has all but halted the delivery of salaries to government workers. Many Palestinians have turned their criticism away from Israel and toward their own leadership, and last week tens of thousands of civil servants launched strikes in protest, the Associated Press reported.
Both Abbas and Haniyeh have urged the workers to return to work, but a union spokesman said the strike would continue.
Details of Monday's agreement were largely unavailable, but Fatah officials said the deal was based partly on Hamas' willingness to accept a U.N. proposal that includes provisions that essentially mean the recognition of Israel, Reuters reported.
Hamas officials did not comment.
Israeli Foreign Ministry spokesman Mark Regev said he hoped a new Palestinian government would accept international demands and that Hamas would release Israeli Corp. Gilad Shalit, whom the group captured in June.
"If that were to happen, we would have a re-energized peace process and new momentum in the Israeli-Palestinian dialogue," he said according to the AP.