Speaking at the launch of a new exhibition at the Titanic Belfast visitor centre, the director claimed that were it not for the shipbuilders' design skills, many more of the passengers on the ill-fated vessel would have died.
"I believe firmly that they are the unsung heroes of Titanic, that kept that ship upright, the stately image that we all think of when we think of Titanic sinking," he said.
"It is important for us to continue to look back at history. There are still lessons to be learned, there were heroes on board the ship that we did not even realise how important they were... and they were Belfast men."
Cameron - whose 1997 blockbuster Titanic won 11 Oscars - opened the new exhibit dedicated to the film with producer Jon Landau. Props and costumes from some of the movie's most memorable scenes are on display, including the original outfits worn by stars Leonardo DiCaprio and Kate Winslet in their final scenes.
Cameron has also donated items from his personal collection of memorabilia, including the ship's wheel and other technical equipment.
"It is a magnificent, dramatic building, the largest Titanic exhibition in the world," he said. "It is also such a celebration of Belfast's contribution to the building of so many fine ships, hundreds of ships, at a point where it was coming into its own as a major industrial power. It is a celebration of the city and the people."
Cameron also revealed that although his film - which was recently re-released in 3D to mark the centenary of the ship's voyage - did not focus on the making of the vessel, there were traditional bodhran drums representing Ireland used throughout the soundtrack.
"We wanted to get that bit of the soul of the ship, which is an Irish soul," he added. "That helps pull on the heartstrings and makes the emotion of that tragic story more powerful for the Irish."