Hamas control over some of the Palestinian security forces is likely to cause alarm in Israel and abroad. The group, sworn to Israel's destruction, is in the middle of forming a government after winning parliamentary elections on 25 January.
"Among those sovereign ministries in the hands of Hamas will be the ministry of the interior," the official said, declining to be identified. He gave no further details.
Israel Radio, quoting sources in Hamas, said the Islamist group planned to name one of its senior officials in the Gaza Strip, Saeed Seyam, to the post.
But Sami Abu Zuhri, a Hamas spokesman, said no decision had been taken on who would hold the job.
He said the group was consulting other factions including the former ruling Fatah movement of Mahmoud Abbas, the Palestinian president, about the cabinet makeup.
Tension has risen between Hamas and Fatah over who will control the Palestinian Authority's overall 60,000 paramilitary police.
The interior ministry controls the civil police, the civil emergency service and the powerful Preventive Security Agency, which is dominated by Fatah. There are some 20,000 security men in the three services.
The Preventive Security Agency was established to curb the activities of militant groups. It was responsible for arresting Hamas militants during a crackdown in 1996 ordered by Yasser Arafat, the late Palestinian president.