Egypt's appointment of a foreign minister known for his hostile views is causing ripples of concern across the Israeli political establishment.

On Monday caretaker Prime Minister Issam Sharraf appointed Nabil Al-Arabi as Egyptian foreign minister, in place of Ahmed Aboul Gheit.

Mr Al-Arabi is a veteran diplomat and was legal adviser to Egypt's delegation to the Camp David conference in 1978, where the Israel-Egypt peace treaty was signed, but he has advocated a significantly tougher diplomatic stance towards Israel than that established by deposed president Hosni Mubarak.

Only recently he wrote in a newspaper article that Egypt should lift the blockade of Gaza and open up its own Rafah border crossing. The crossing has remained closed, or under close watch, for the four years since Hamas took control of Gaza. Mr Al-Arabi wrote that the blockade is "contrary to the rules of international humanitarian law which prohibits the siege of civilians, even in times of war".

As a former ambassador of Egypt to the United Nations, Mr Al-Arabi was involved in a large number of UN resolutions against Israel.

Unlike Mr Mubarak's inner circle, Mr Al-Arabi argued for making any progress in the "normalisation" of Egypt's relations with Israel conditional on the state of the conflict between Israel and the Palestinians. He is also less resolutely opposed to co-operation with movements such as Hamas and Hizbollah.

The delays in the resumption of Egyptian natural gas flow to Israel, which was suspended on February 5 following sabotage of the pipeline in Sinai, is also a major source of worry. Egypt promised to swiftly repair the pipeline and received Israel's agreement to deploy more troops to Sinai to protect the peninsula, but the fact that over a month has passed and there is still no clear date for the renewal of supplies has led to widespread concern.

Within the Egyptian opposition, there have been calls not to supply natural gas to Israel until a breakthrough has been achieved with the Palestinians.

Following initial worries at the departure of Mr Mubarak, a long-time strategic ally, Israeli fears were allayed somewhat after the Egyptian army took control of affairs.

The Israeli defence establishment has close behind-the-scenes contacts with the Egyptian military and Defence Minister Mohammed Tantawi was quick to call his Israeli counterpart, Ehud Barak, and tell him that the temporary administration would make sure that the peace between the two countries would remain stable.

"We still do not believe that there is a risk to the Camp David agreement," said a senior Israeli official this week, "but there are worrying signals, such as the appointment of Al-Arabi, the natural gas and the inclusion of the Muslim Brotherhood in political talks. We may see the emergence of a Turkish-style government in Cairo, one that will be much more critical of Israel without actually breaking off ties."

One senior Egyptian figure who sounded a more careful note was former foreign minister and Arab League Secretary General, Amr Moussa, who is expected to make a run for the presidency when elections are held in Egypt later this year. "We as Egyptians have a responsibility to lay the foundations for peace," he said this week.