Mr Blair responded: "I agree entirely with what you say...we hope that people realise these are people that, in many cases sacrificed their lives in order that this country remained free."
Tony Blair said that the film - a huge success in the US and number four in the UK box office chart on its opening weekend - was an "affront" to British sailors.
The film portrays the capture of the Enigma coding machine from a Nazi submarine - an event which changed the course of World War II - as an American rather than British, operation.
It was described in the Commons as an "affront" to British sailors killed in the operation. Mr Blair said that he entirely agreed.
The Culture Secretary, Chris Smith, has already said he will raise the issue in Hollywood for inaccurately glossing over the real story. He described the film as a "little galling".
Speaking during Question Time on Wednesday, a Labour MP, Brian Jenkins, said the film, was an "affront to the memories of the British sailors who lost their lives on this action".
Mr Blair responded: "I agree entirely with what you say...we hope that
people realise these are people that, in many cases sacrificed their lives in
order that this country remained free."
According to U-571, it was the US Navy that recovered the code machine, but the device was really captured by the crew of HMS Bulldog.
They disabled and seized German submarine U-110 to retrieve the device.
Fictional
At the end of U-571, prior to the credits, it is made clear that the movie is fictional but inspired by real events.
Critics have pointed out the film-makers could have made successful movie, which would have been just as enjoyable, by creating some new incident rather than distorting history.
A group of MPs, led by Chorley's Lindsay Hoyle, has already expressed "regret" about the film in a Commons' motion.
They noted: "(That British sailors) risked their lives to board the stricken
submarine, facing the danger that it might sink at any time.
"That members of the boarding party were decorated for their heroism in retrieving the encoding device and that King George VI described their actions as perhaps the most important single event in the war at sea.
"And regrets that Hollywood has chosen to distort the truth and detract from the valour of the British sailors concerned by appropriating the story for its own financial gain."
And Mr Smith has said: "I think one of the things we need to make clear to Hollywood is, yes you're in the entertainment business but people see your movies, they're going to come away thinking that's information not just entertainment.
"You've got to make it clear where the dividing lines between these things lie."