RUC Chief Superintendent Harry Breen and Superintendent Bob Buchanan were gunned down in Co Armagh while on their way home from a high-level meeting at Dundalk Garda Station in 1989.
Made public on Tuesday, the Smithwick report confirmed long-held suspicions that there was an IRA mole in the Dundalk Garda station.
The judge presiding over the eight-year tribunal into the murders was satisfied there was collusion between the IRA and someone in An Garda Siochána which led to the attack.
But Mr Adams has said the report's findings are "contradictory" and that the officers had a laissez-faire disregard for their own security.
"The Guards, and the judge criticises this, didn't appear to be dealing with them in security that was required of men of their profile and standing," he said.
"The RUC in the North, similarly, weren't paying heed to this.
"And here they are, on an unapproved road, going through republican South Armagh, at a very bitter and tense period of the conflict. So when that happens nobody needs to infiltrate anything."
Mr Adams’ comments are deeply insulting and offensive. This was a case of brutal pre-meditated murder by the Provisional IRA and nothing Mr Adams says will ever change that fact. At a time when Dr Haass is looking at ways of dealing with legacy issues it is difficult to see how Mr Adams’s comments square with his oft-repeated calls for reconciliation and truth.
Theresa Villiers, NI Secretary of State
But his opinion has outraged others, SDLP Justice spokesperson Alban Maginness said his "attempts to place blame on the victims is nothing short of appalling".
"To blame victims for being murdered and try to apportion responsibility to them for being killed is just vile.
"Victims and their families deserve our support and our sympathy.
"It is clear that Sinn Féin will do all they can to rubbish the Smithwick Report which was completed after a painstaking process but to blame victims for being killed is a new low."
DUP MLA Arlene Foster has described the comments as "beneath contempt".
"Those responsible for this murder were the IRA gang who carried it out and those who assisted them with information."
Unfortunately in Northern Ireland we have a definition of a 'victim' which places the IRA terrorists who murdered Chief Supt Breen and Supt Buchanan on a par with their victims.
Arlene Foster, DUP MLA
"I would hope that all those who are rightly expressing such horror at Gerry Adams' comments will back their words up with action and state their full support for a change to the definition of a 'victim'."
She continued: "It is Gerry Adams' laissez-fair attitude to the truth that has been exposed as he shuns reality in favour of a world where republicans are never guilty of any crime.
"Outside the Sinn Féin bubble, the vast majority of people on both sides of the border are horrified at the findings of Judge Smithwick, and now by these grossly offensive comments," she concluded.
While UUP Mike Nesbitt slammed his remarks as "grossly insensitive".
"This morning Gerry Adams said he was very mindful of the suffering of the Breen and Buchanan families," he said.
"If he was so mindful of the families he would not have went on to describe the evidence the conclusions of the Smithwick report were based on as 'tittle tattle'.
"He didn't do much better when he described the officers' attitude towards their own safety as 'laissez faire'."
It's a revelation of another dark patch in Ireland's recent history.
Taoiseach Enda Kenny
On Tuesday Irish Tánaiste Eamon Gilmore said he was "appalled and saddened" by the findings and apologised without reservation to the Breen and Buchanan families, as did Irish Justice Minister Alan Shatter.
Mr Shatter said on Wednesday he found the Louth TD's contribution "nauseating".
He said: "The truth is, you had two respected senior members of the RUC barbarically murdered in cold blood, by individuals with whom Mr Adams was associated (with)."
Taoiseach Enda Kenny has also reacted while on a trade mission in Japan and reiterated the apology.
"I found it absolutely shocking," he said.
"The Minister for Justice has already delivered an apology on behalf of the government and I endorse that apology fully without reservation."
Mr Kenny said he would write to the families involved and was willing to meet with them if deemed appropriate.
This report should not and will not distract us from the strong working relationships we enjoy with our colleagues in An Garda Siochána.
PSNI Chief Constable Matt Baggott
Also reacting on Wednesday was Garda Commissioner Martin Callinan who said the report had identified a betrayal from within the force.
"It's a source of great disappointment that no-one has been made amenable to date for their cowardly murders," Mr Callinan said.
"These were colleagues of ours who were travelling to Dundalk garda station to take part in discussions with our colleagues in relation to very serious policing and security matters."
Mr Callinan said he accepted the report's conclusions and also apologised unreservedly for any wrongdoing on behalf of the force.
"I'm absolutely horrified that any member of An Garda Siochana would betray the fundamental principles of An Garda Siochana, and the disloyalty shown by whoever was involved in this killing," he added.
PSNI Chief Constable Matt Baggott also commented, he said it was important to acknowledge the suffering of the Breen and Buchanan families and expressed his sincere sympathy to them.
"Chief Superintendent Harry Breen and Superintendent Robert Buchanan were highly regarded police officers who made a great contribution to the RUC and their loss was sorely felt," he said.
"We will take time to study the findings of this report in detail and I will be discussing it with the Commissioner and the Justice Ministers in the coming weeks."
Mr Baggott stressed that the findings would not affect working relationships between the two police forces.
He added: "We have well established protocols, excellent cross-border cooperation and we remain resolute in our determination to build on these solid foundations and our commitment to jointly combat crime and to protect all our citizens."
Meanwhile, a former Garda has rejected the tribunal's finding that he was trusted by the IRA and helped members get their hands on false passports.
Retired Garda sergeant Leo Colton was one of three named officers cleared by the Smithwick Tribunal of colluding with the IRA on the day the police officers were murdered.
But he dismissed other findings against him by Judge Peter Smithwick.
A statement issued through Dundalk based solicitors Dermot Lavery and Co. said: "Retired Sergeant Leo Colton respects the integrity and the hard work carried out by the chairman and the tribunal team but totally rejects the finding that he was involved with the IRA.
Leo Colton was not, is not and never would be involved with the IRA or any other subversive organisation.
Dermot Lavery and Co solicitors
Judge Smithwick found Mr Colton assisted the Provisional IRA in 1995 and 1996 by getting his former colleague, Finbarr Hickey, to sign false passport applications.
The former Garda was on duty in Dundalk on 20 March 1989, the day the RUC officers were ambushed.
However, the tribunal found neither Mr Colton, or the two other former gardaí questioned - Mr Hickey or Owen Corrigan - were involved with any collusion on the day of the double murder.