By Abdel-Sattar Hatita

Cairo - Over 100 mainly Islamist lawmakers walked out of Egypt's parliament on Sunday to protest government moves to push through constitutional laws that opponents fear will entrench the ruling party's grip on power.

The parliament, dominated by President Hosni Mubarak's National Democratic Party, is expected to approve the proposed amendments with a vote on Tuesday. A public referendum on the proposed changes would then be held early next month.

Analysts say the measures, which went to debate on Sunday, appear to target the Muslim Brotherhood, the country's largest opposition movement, because they include a ban on political work based on religion and give the state sweeping security powers.

London-based Amnesty International has called the proposed laws "the greatest erosion of human rights" since emergency laws were reinstated in 1981 after the assassination of President Anwar Sadat. The government has said the amendments are part of political reforms.

"We have decided to boycott these sessions to clear our conscience ... and let the National (Democratic) Party bear the responsibility before the people," Mohamed el-Katatny, head of the Brotherhood's parliament bloc, told reporters after leaving the parliament session.

More than 100 lawmakers of the 454-seat legislature, mainly Islamists and a handful of independents, protested outside parliament as the session got underway. Some carried yellow banners saying the laws spelt the end of free elections and civil freedoms.

"Judgment Day will be tough on you," independent legislator Alaa Abdel-Moneim told ruling party lawmakers before leaving the chamber. Majority leader Abdel-Ahad Gamaleddin criticised the opposition walkout as "intellectual terrorism".

One banner, next to an opposition lawmaker who was praying, read: "No to the constitutional coup."

At the heart of the opposition's fury over the amendments is an anti-terrorism clause that gives police greater arrest powers and wide authority to monitor private communications. The amendments would also weaken the role of judges in overseeing elections.

Some political analysts say the authorities want to stop the Brotherhood, whose members won 88 parliament seats in 2005, before it makes more electoral gains that could help it eventually mount a serious political threat to the ruling party.

Security forces have arrested 47 Brotherhood members over the past week, cranking up a three-month crackdown that has seen the group's third-in-command Khairat el-Shatir arrested and charged along with 39 others of money laundering and terrorism.

Around 270 Brotherhood members are now in detention.