"The government decision is that fuel doesn't go in because it will be stolen by Hamas and it'll be used by them to power rockets that are fired into Israel to kill our people," Regev told US news broadcaster on Monday.
He added that a small amount of fuel was let in through the Rafah crossing on the Egypt-Gaza border but ended up stolen. Israel thinks that fuel was diverted to military causes.
Regev underlined that Israel would not authorize fuel entering Gaza even if Hamas freed all hostages.
The first batch of international humanitarian aid was delivered to the Gaza Strip on Saturday by a UN convoy through the Rafah border crossing. The second convoy carrying aid arrived on Monday.