Netanyahu, speaking Sunday at the start of the weekly Cabinet meeting, said radical Islamist groups have taken the place of the Syrian army along the border, Israel Radio said.
"We know that today on the other side of the border with Syria, the Syrian army has moved away and in its place, global jihad elements have moved in," The Jerusalem Post quoted Netanyahu as saying.
He said the unstable situation in Syria requires Israel to take steps similar to those taken on the border with Egypt, where a 144-mile border fence is almost complete.
Netanyahu said he has instructed Defense Ministry staff to plan "first and foremost on our border with Syria." Israel, he said, needs to defend itself on the northern border not only from infiltrations but also from terrorist elements, the Post reported.