Israel has unveiled plans for a security barrier running along the Egyptian border to keep out militants and African migrants.
Announcing the £167 million) project, Benjamin Netanyahu, the Israeli prime minister, said: "This is a strategic decision to ensure the Jewish and democratic character of the state of Israel.
"Israel will remain open to war refugees but we cannot allow thousands of illegal workers to infiltrate into Israel via the southern border and flood our country."
Israeli police believe 100 to 200 people cross from the Sinai peninsular every week.
The new barrier will initially be built in two sections, one near the Red Sea city of Eilat and another on the edge of the Gaza Strip, where Egypt has already begun construction of an underground steel wall to close off smuggling tunnels.
The fence will include radar to detect human movement. Eventually the whole border will be sealed.
Israel is also continuing to build its controversial barrier in and around the occupied West Bank. The government says the 400-mile system of fences and concrete walls is needed to prevent suicide bombers from launching attacks.
However, Palestinians, who often refer to it as the "apartheid wall", believe it is part of a land grab as some portions of the West Bank are contained within the Israeli side of the barrier.
There are about 15,000 asylum seekers in Israel, according to the United Nations Refugee Agency.
Eritreans fleeing national service and an oppressive government are the most numerous, along with others from Ethiopia and Sudanese escaping war-torn Darfur.
Some pay hundreds of dollars to Bedouin guides to escort them to the border, where a low fence separates Israel from Egypt.
Tensions along the border between Gaza and Egypt have escalated in recent weeks.
A spokesman for the Egyptian foreign ministry said the new barrier was purely a matter for Israel.
Telegraph.co.uk. has contributed to the report.