The panel investigating last month's botched raid on a Gaza-bound flotilla will soon receive greater authority after its chairman, retired justice Jacob Turkel, told the government the committee could not do its job without expanded investigative powers.

Channel 2 television reported last night that Turkel even threatened to resign if his demands were not met. A spokesman for his committee, however, denied this.

Currently, the panel has a very limited mandate. It is only supposed to determine whether Israel's efforts to stop the flotilla from reaching Gaza accorded with international law, and whether the soldiers' use of force was proportionate. It has no power to subpoena witnesses and cannot draw personal conclusions against those involved in the raid.

Turkel, however, wants to turn it into a full-fledged governmental inquiry committee with real teeth. That would allow it to subpoena witnesses and documents, warn those who testify before it that the panel's findings could harm them, and hire outside experts in relevant fields.

The ability to issue warnings is necessary to enable the panel to draw personal conclusions against those involved in the incident; for instance, to recommend that certain officials be dismissed or denied promotion. Warnings also enable witnesses to be prosecuted for perjury if they are later found to have lied to the committee - though in reality, few investigative committees have ever recommended perjury prosecutions.

Feverish negotiations have been underway over the last few days between Prime Minister Benjamin Netanyahu, Justice Minister Yaakov Neeman, Defense Minister Ehud Barak and Turkel in an effort to find a formula that will satisfy the demands of both Turkel and the government. One of the biggest problems is that Barak refuses to let the panel question any Israel Defense Forces soldiers or officers aside from Chief of Staff Gabi Ashkenazi and Military Advocate General Avichai Mendelblit. Barak fears that soldiers will be reluctant to carry out missions if an inquiry panel can later penalize them for anything that goes wrong.

But both army and government sources predicted that Turkel would ultimately agree to keep this restriction in place. If so, other soldiers and officers would instead testify before the internal army probe into the raid's operational aspects that is headed by Maj. Gen. (res. ) Giora Eiland, who would then present his findings to the Turkel Committee. Eiland's report is due to be completed by July 4, though there could be a slight delay.

Government sources also said there would be no change in the list of topics the panel is authorized to probe. That means the committee will still not be authorized to examine the way the government approved the raid and whether it considered other alternatives.

When he broached his demands to Neeman a few days ago, Turkel listed two key issues. First, he insisted on the full investigative powers of a state commission of inquiry - something the relevant minister is authorized to grant a governmental inquiry committee if it is headed by a current or former judge. Such powers were granted to the governmental panel that investigated the Second Lebanon War of 2006.

In addition, Turkel said he wants to expand the committee from three members to five, not including the two foreign observers.

Turkel's demand for wider powers comes amid widespread media criticism that has painted the committee as being designed mainly to retroactively justify the blockade of Gaza, the use of force to maintain it and the bloodshed on board the Mavi Marmara when naval commandos were attacked by passengers wielding knives and iron bars. The commandos, who had been ordered to seize control of the ship and divert it to Ashdod Port, opened fire in self-defense.

But it appears that what really moved Turkel to demand change was the criticism from other jurists about the panel's limited mandate, as well as a petition to the High Court of Justice by the Gush Shalom movement demanding that the committee be given broader powers. The court was to hear that petition today, but received an urgent request for a 10-day postponement from the State Prosecutor's Office yesterday on the grounds that the government is currently considering expanding the committee's mandate, which would make the petition unnecessary.

The request also noted that in light of the possible change in its mandate, the Turkel Committee will not hold its first session until July 11. Netanyahu is expected to be the first witness.

The Prime Minister's Office said in a press statement yesterday that it sees no reason why Turkel's demand for greater investigative powers cannot be met. But it stressed that these expanded powers would not include the right to question soldiers.

A senior government source explained that both Netanyahu and Barak were adamantly opposed to the idea that every soldier or officer who participated in the raid would now have to hire a lawyer to defend him before the committee.

The revised mandate is currently being prepared by Neeman, who will then have to submit it to the cabinet for approval. That could happen as soon as the regular cabinet meeting this coming Sunday.

Meanwhile, Turkel has informed the two foreign observers - David Trimble, a Nobel Peace Prize laureate who formerly served as first minister of Northern Ireland, and Ken Watkin, a former Canadian judge advocate general - that they will be allowed to question witnesses freely during the hearings and examine any material they wish. The panel's tentative plan is to first have all the witnesses testify, then examine all the printed material, including Eiland's report, and finally call the witnesses back for further questioning.

Turkel has pledged to try to complete the probe as quickly as possible, but it is expected to take several months. Many, though not all, of the hearings are expected to be open to the public.

In addition to the Turkel Committee and Eiland's panel, State Comptroller Micha Lindenstrauss is planning his own probe into issues such as the government's decision-making that are currently outside the Turkel Committee's purview. However, he does not plan to begin until after Eiland's probe is finished, so that he will have Eiland's findings before him.