The new government is made up entirely of Hamas members, with many holding positions at the Islamic University in Gaza, the Ma'an News Agency reported.
The United States is among a group of nations, along with the European Union, that considers Hamas a terrorist organization.
"The reshuffle is an administrative step and is not against reconciliation," Haniyeh said.
Haniyeh said the new government would step down when a national unity agreement ending division with Fatah is signed. Fatah is a major Palestinian political party and is the largest element of the Palestine Liberation Organization.
The announcement comes as Prime Minister Salam Fayyad is holding talks to form a new government. He was appointed prime minister under the Palestinian Authority in the West Bank.
The West Bank government resigned last month. President Mahmoud Abbas earlier this month granted Fayyad a two-week extension to form a new government.