Israel's parliament approved harsh new penalties on illegal immigrants yesterday in an effort to stop mainly sub-Saharan Africans seeking refuge from conflict and poverty.

Although the law stopped short of enacting some of the most draconian penalties sought by the government, it has provoked widespread criticism from human rights groups. The law allows the state to imprison illegal migrants for life if they commit certain crimes and detain them and their children for three year terms simply for being caught entering Israel.

Nitzan Horowitz, a parliamentarian, called the new law a "stain" on Israel's legal code. And the retired judge Boaz Okon, the legal affairs analyst of the Yediot Ahronot newspaper, called the law "unlimited licence to employ terror against anyone who reaches Israel."

The government estimates 50,000 Africans have illegally entered Israel through its border with the Egyptian Sinai desert since 2005.

While Israeli officials have argued that the majority are economic migrants seeking a better standard of living, advocacy groups contend many are genuine refugees who face retribution if forced to return home.

The issue has proved politically sensitive, with liberals arguing that Israel has a special obligation to adopt a lenient attitude to migrants because of the Jewish history of persecution in Europe and elsewhere

The Association for Civil Rights in Israel labelled the law "draconian and immoral". "Its entire purpose is to deter refugees from entering Israel," it said.