GENEVA, Aug 4 (Reuters/Robert Evans) - Two United Nations investigations into Israel's May 31 interception of a Gaza-bound aid flotilla will not overlap but rather complement each other, a senior diplomat at the UN Human Rights Council said on Wednesday.

A council inquiry will address perceived violations of human rights and humanitarian law, the body's incoming head said, while a probe set up by UN Secretary General Ban Ki-moon will examine ways of preventing such incidents in the future.

Some diplomats say Ban, who announced his team on Monday, was annoyed at the decision of the council -- where Islamic states and allies have a majority -- to set up its own probe.

Israel has said it will not work with the UN council, which many nations feel has focused on Israeli treatment of Palestinians at the expense of other rights issues worldwide, or allow it into Israeli territory, but will cooperate with Ban's team, which will include an Israeli and a Turk.

Incoming council president Sihasak Phuanketkeow of Thailand told a news conference the 47-nation body was taking up its mission with open minds and would not duplicate the Ban probe.

This mission is not about finger pointing, but establishing facts, said Sihasak, who put together the council team.

He said its members were chosen because they had made no public comment on the incident.

Nine pro-Palestinian activists, eight Turks and a Turkish-American were killed on one boat in the flotilla when Israeli marines took it over in international waters.

Other activists on the boat -- whose Turkish sponsors said the flotilla aimed to break Israel's sea blockade of Gaza -- said only minor resistance was offered to the marines. But Israel said they were attacked with iron bars and other weapons.

The three in the council probe -- a British and Trinidadian judge and a Malaysian human rights activist -- will begin to prepare their mission in Geneva next week, said Sihasak, Thailand's ambassador to the UN's European headquarters.

Apart from the Israeli and Turk, who are yet to be named, Ban's team will be headed by former New Zealand prime minister Geoffrey Palmer and outgoing Colombian President Alvaro Uribe.

Israel has already held its own military inquiry into the incident, which further damaged Israel's already deteriorating relations with Turkey, and a civilian one is now under way.