A prominent Senate select committee has voted to approve a 6,000-page report of its investigation into controversial interrogation techniques adopted by the CIA during the so-called "war on terror" that is believed to show that the methods, widely denounced as torture, produced little valuable intelligence.

The Senate select committee on intelligence voted by nine to six on Thursday to adopt the report, which will now be passed to the Obama administration for review. It is the result of a mammoth three-year investigation into the exceptional CIA interrogation methods that were permitted by the Bush administration.

Dianne Feinstein, the Democratic head of the committee, has called the inquiry the "most definitive review of this CIA programme to be conducted".

The positive vote was greeted warmly by human rights groups. Melina Milazzo of Human Rights First said: "By voting to adopt this report, the committee has sent a clear message that torture and abuse have no place in US intelligence operations," said Human Rights First's Melina Milazzo.

The majority Democratic members of the committee were joined by one Republican senator, Olympia Snowe of Maine, in backing the report. However, lack of co-operation from the remaining Republican members of the panel could prevent the document ever seeing the light of day.

Some of the top retired military leaders in the US have appealed to the committee to adopt the report and to publish it with as few redactions as possible. A joint letter from 26 of them – including retired marine generals Joseph Hoar, former commander-in-chief of United States Central Command, and Charles Krulak, former commandant of the marine corps – was sent to the committee on Wednesday protesting the Bush administration's use of torture.

"As retired generals and admirals," the letter reads, "we know that torture and cruel, inhuman and degrading treatment produces unreliable results and often impedes further intelligence collection. Torture is unlawful, immoral and counterproductive."

Yet, the letter continues, it is still argued today that torture led to the killing of Osama bin Laden, and that the CIA should still have the power to engage in such practices. "The committee's comprehensive review will demonstrate the negative impact of torture on our national security and stand as a testament against those who urge otherwise."

The Senate has spent the past three years investigating the CIA's detention and enhanced interrogation techniques for the period beginning in 2002 after 9/11 and the start of the war in Afghanistan and ending in 2009 when incoming President Barack Obama banned the use of torture. The controversial practices included waterboarding, stress positions, forced nudity, beatings and sleep and sensory deprivation as well as the "rendition" or extra-legal extradition of terror suspects to a network of secret prisons.

The report runs to almost 6,000 pages and is based on more than 6m pieces of information. Feinstein has said that the report is "comprehensive, it is strictly factual, and it is the most definitive review of this CIA programme to be conducted".

It is believed to conclude that the "enhanced interrogation techniques" adopted by the CIA during the Bush years did not produce any major breakthroughs in intelligence. The finding, if confirmed, would contradict previous claims by President Bush himself, his vice-president Dick Cheney and other prominent Bush administration figures who said that extreme interrogation methods allowed the CIA to extract valuable intelligence from a small number of high-level detainees.

Most incendiary have been the claims that such brutal techniques were seminal in tracking down and killing Bin Laden in his hideout in Abbottabad, Pakistan in May 2011. The Senate report is believed to conclude that effective torture did not play a central role in finding the al-Qaida mastermind.

Earlier this year, Feinstein said: "The suggestion that the operation was carried out based on information gained through the harsh treatment of CIA detainees is not only inaccurate, it trivialises the work of individuals across multiple US agencies that led to Bin Laden and the eventual operation."

The controversy over the role that extreme interrogation methods such as waterboarding played in the hunt for Bin Laden has resurfaced this week with the release of the feature film Zero Dark Thirty which contains graphic re-enactments of the techniques and implies the methods succeeded in extracting key information. Several US senators have protested the portrayal.

Paradoxically, the brutal techniques adopted by the CIA during the Bush years were based on those used by Communist Chinese interrogators during the Korean war. US soldiers being sent to the far east were trained to recognise the techniques so that they might resist them more effectively should they be captured.

It is not yet clear what strategy the Republican senators on the select committee will take. They essentially boycotted the investigation in 2009 in protest at the decision by Obama to ask the department of justice to launch a separate inquiry into whether the CIA programme was in breach of the law (earlier this year the DoJ dropped its investigation with no criminal charges).

Feinstein said the decision on whether or not to release the report would be taken at a later date.