The Raging Bull star, 72, recently revealed his 18-year-old son Elliot suffers from the developmental disorder after defending his decision to include a controversial anti-vaccination documentary in the line-up of his Tribeca Film Festival.

Vaxxed: From Cover-Up to Catastrophe, directed by anti-vaccine movement leader Andrew Wakefield, had been set to screen at the annual New York event on 24 April (16), but it was pulled last month (Mar16) amid a growing uproar from medical professionals and other filmmakers involved in Tribeca, which opens on Wednesday (13Apr16).

De Niro has now admitted he has some regrets about agreeing to remove the documentary from the festival, explaining he was busy shooting another movie when he had to make the "knee jerk" reaction with Tribeca co-founder Jane Rosenthal.

He still stands by the film, which questions the scientific research that doctors claim proves there is no link between autism and vaccines, insisting it is worth checking out simply to see all sides of the story.

"I think the movie is something that people should see," he said on U.S. breakfast show Today. "There was a backlash that I haven't fully explored, but I will, and I didn't want it to start affecting the festival in ways that I couldn't see, but definitely there's something to that movie...

"I, as a parent with a child who has autism, am concerned. I want to know the truth. And I'm not anti-vaccine; I want safe vaccines..."

De Niro goes on to reveal his wife Grace Hightower, Elliot's mother, believes there was a significant shift in their son's behaviour after he was vaccinated.

Asked if he recalls Elliot changing "overnight", the heated actor responded, "My wife says that. I don't remember. But my child is autistic. And every kid is different. But there is something there that people aren't addressing, and for me to get so upset here today - on the Today show, with you guys - means that there's something there."

He is urging scientists to further explore "how the vaccines are dangerous... to certain people who are more susceptible", insisting they should be more open to addressing what is a continuing issue.

"The thing is, to shut it (the theory) down, there's no reason to," De Niro added. "If you're a scientist, let's see, let's hear it. Everyone doesn't seem to want to hear much about it..."

"There is a link... there's certain things... I don't know, I'm not a scientist, but I know (there's something) because I've seen so much reaction. Let's just find out the truth," he concluded.