Egypt says it has begun to install cameras and motion sensors along the border with Gaza to try to stop weapons smuggling by Palestinian militants.
Tighter surveillance of the tunnels is one of Israel's key conditions for maintaining the ceasefire that ended its three-week offensive against Hamas.
The tunnels were used to smuggle food and medicine, as well as arms.
Israel bombed them, but when the fighting stopped some were still usable and others have been repaired.
Egyptian security sources said the authorities had begun installing the equipment in the last few days along the 14km (8-mile) border with the help of American, French and German expertise.
Reuters news agency quoted the sources as saying they hoped the equipment would detect any new tunnel-building activity in the area.
The United States has pledged $32m in detention equipment and army engineers are providing technical assistance on the ground, AFP news agency said.
The tunnels were one of Israel's main targets during its offensive.
Hamas and many Palestinians say the tunnels are a vital source of basic necessities so long as Gaza's borders with Israel and Egypt remain blocked.