By Imogen Foulkes BBC correspondent in Geneva

The Israeli barrier will be one of the controversial issues

The commission is debating a range of controversial issues, including the effect on the Palestinian people of Israel's West Bank barrier.

The acting high commissioner has asked for cool heads and reasoned argument.

A Mexican proposal calls for an investigator to examine the impact of the war on terror on human rights.

Anti-terror measures

Acting high commissioner Bertrand Ramcharan supported the proposal, saying the UN Security Council had "already made itself clear on this issue".

He said it was the duty of governments to tackle terrorism "within the law, with respect for the principle of proportionality and with respect for fundamental human rights".

Mr Ramcharan, while paying tribute to the victims of the Madrid attacks, clearly does not want terrorism to overshadow other human rights issues.

'Lacking in credibility'

He reminded delegates that other subjects, such as the trafficking of women and children, needed attention too.

Above all he said, the Commission must not forget that poverty is a big factor in the abuse of human rights.

"Anyone who thinks that he or she can advance the human rights cause in the contemporary world without tackling this issue of mass poverty, is engaging in delusion," he said.

It will be a difficult six weeks for the Human Rights Commission: the debates on terrorism and on Israel's security barrier are bound to expose political divisions.

At the same time, the commission is facing criticism from human rights activists that its work is irrelevant and lacking in credibility, because it is claimed, powerful countries with poor human rights records regularly escape censure.