Cardinals, speaking with the authorisation of the Vatican, have called for the Hollywood version of Dan Brown's bestselling novel to be boycotted.
They say the theme of the film - that Jesus Christ had children with Mary Magdalene and that hardline Catholic movement Opus Dei covered up his secret life - is highly blasphemous.
But Oscar-winner Hanks said objectors to The Da Vinci Code are taking the film too seriously, telling the Evening Standard: "We always knew there would be a segment of society that would not want this movie to be shown.
"But the story we tell is loaded with all sorts of hooey and fun kind of scavenger-hunt-type nonsense.
"If you are going to take any sort of movie at face value, particularly a huge-budget motion picture like this, you'd be making a very big mistake.
"It's a damn good story and a lot of fun... all it is is dialogue. That never hurts."
The Da Vinci Code book has sold more than 40 million copies since it was published in 2003. The film, released by Sony Pictures division Columbia Pictures, is set to be one of the year's most successful when it is released worldwide on 19 May.
As well as Hanks, it stars Audrey Tautou and Sir Ian McKellen and is directed by Oscar winner Ron Howard.
The Da Vinci Code receives its world premiere at the Cannes Film Festival next Wednesday.
Calls for Christians to boycott it have been led by Archbishop Angelo Amato, the number two official in the Vatican doctrinal office, which was headed by Pope Benedict until his election last year.
Amato described the novel as "stridently anti-Christian" and called for believers to "reject the lies and gratuitous defamation" in the book.
He added: "If such lies and errors had been directed at the Koran and Holocaust they would have justly provoked a world uprising.
"Instead, if they are directed against the church and Christians, they remain unpunished. I hope you will boycott the film."
Cardinal Francis Arinze, a Nigerian tipped to be Pope last year, went even further.
He said: "Christians must not just sit back and say it is enough for us to forgive and forget. Sometimes it is our duty to do something practical.
"Some know legal means which can be taken in order to get the other person to respect the rights of others."
The Catholic church here is taking a more relaxed line, arguing that in the face of the film's blockbuster appeal, calling for a boycott would be pointless.
Cardinal Cormac Murphy O'Connor, head of the Roman Catholic church in England and Wales, told the Jonathan Dimbleby programme on ITV1 on Sunday: "I think it's a harmless thriller. If people want to read it they can and people who read it should realise it is fiction."
But some prominent UK Catholics favour a harder stance. Piers Paul Read, himself a best-selling novelist, said:
"I am for the boycott. I don't think Catholics should put money into the pockets of people who have invented lies about the church."
Another eminent Catholic, socialite Claus Von Bülow, said: "I am not going to see The Da Vinci Code. This has nothing to do with its historical claims but because I found the book unreadable."