Israel's Chief of the General Staff Eyal Zamir has declared that the troops' pullback line in Gaza is the new border between Israel and the Palestinian territory.

During a visit to forces in northern Gaza on Sunday, he said the so-called "yellow line" was the new border, a forward defensive line for Israeli border communities and also an attack line.

The yellow line represents a new division of territory in the Gaza Strip and extends between 1.5 and 6.5 kilometres into the coastal area. Israel thus controls slightly more than half of Gaza where more than 2 million Palestinians live.

Before the new border was drawn, the Gaza Strip was around 41 kilometres long and between 6 and 12 kilometres wide.

"We will respond with full force to any attempt to threaten our forces," Zamir said, adding Israel would not allow Hamas to re-establish itself in the Gaza Strip.

Under a ceasefire agreed with the Islamist group, the Israeli army has withdrawn behind the yellow line, which gets its name from yellow concrete blocks and signs on the pullback line.