A panel of medical experts, appointed two years ago by a court in the United States, has ruled there is no proof that silicon breast implants are harmful to health.

The experts said tests had shown any toxic effects were few in number and questionable in significance.

Correspondents say their findings -- although not legally binding -- could have a significant bearing on thousands of court cases throughout the world, where women maintain they've suffered after breast implant operations.

One company Dow Corning has already offered more than three billion dollars in settlement of actions against it.

Lawyers representing those affected say the study was too narrow, and failed to address the key question of what happened when the implants leaked.