Dr. Omar Abdel Razek, 52, was arrested Monday in Salfit near Nablus, Ynetnews.com said Tuesday.
Razek is suspected of involvement in terrorist activity, the Web site said quoting a Palestinian television report.
Israeli soldiers searched his home and confiscated a number of computers before detaining him. Hamas Parliament member Muna Mansur, who reported the arrest, expressed fears that Israel may be planning to arrest additional Hamas members.
This is not the first time Razek has been arrested by Israel, the Web site said, noting he was arrested along with other Hamas members following the abduction of Israeli soldier Gilad Shalit in June 2006.
Shalit was serving near the Gaza border when he was abducted and taken to Gaza, where he has been held incommunicado ever since.
Razek was released from prison in April 2008.