A UN Commission of Inquiry consisting of independent human rights experts said on Thursday in Geneva that they had reasonable grounds to believe that Israeli soldiers violated the international rules of war and human rights law by targeting unarmed, non-violent protesters.

"Some of those violations may constitute war crimes or crimes against humanity, and must be immediately investigated by Israel," Commission Chairman Santiago Canton said as he presented the report on the sidelines of the UN Human Rights Council.

UN rights investigators usually do not draw definite conclusions, but leave final judgement to national courts or international tribunals.

The protests began in late March last year at the border fence separating Israel and the Gaza Strip.

Tens of thousands of Palestinians took part in the demonstrations for their right of return to the territory of today's Israel.

The commission acknowledged that some demonstrators were members of armed groups and that the protest organisers, which included militants from the Hamas movement, encouraged the use of incendiary kites and balloons, causing damage and fear in southern Israel.

However, the commission report disputed Israel's stance that the weeks of protests were a guise for terrorist activities. Rather, the investigators concluded that the nature of the demonstrations was civilian.

"The commission finds that these protests were a call for help from a population in despair," Canton said.

"The commission calls on Israel to lift the blockade of Gaza," he said, while also urging Hamas and the Palestinian Authority to improve the living situation in Gaza.

The commission said it would hand over information about those who are allegedly responsible for the rights violations to UN rights chief Michelle Bachelet, who could share it with international justice bodies such as the International Criminal Court in The Hague.

Australian Associated Press