A US judge on Thursday ordered Johnson & Johnson to pay $344 million for false and deceptive marketing of pelvic mesh products used by tens of thousands of women in California.

The suit in San Diego was part of a series of claims the company has faced worldwide over the mesh products, designed to support weakened muscles holding up the pelvic organs.

San Diego County Superior Judge Eddie Sturgeon ruled that Johnson & Johnson knew of the potential risks and side effects of its products before their launch and did not disclose these risks in educational and marketing materials provided to doctors and patients.

Sturgeon in his ruling said "complications could be so severe that mesh removal would be necessary but, unlike other implants, removal is difficult and harmful and can take multiple surgeries.

"Johnson & Johnson also knew that some of the most severe complications of mesh can be irreversible," the judge wrote.

Women who have used the devices say the side-effects include incontinence, infection, bleeding and chronic pain.

"Johnson & Johnson knew the danger of its mesh products but put profits ahead of the health of millions of women," California Attorney General Xavier Becerra said after the ruling.

"Today we achieved justice for the women and families forever scarred by Johnson & Johnson’s dishonesty."

Becerra's office sued the company in 2016 after a years-long multi-state probe concluded that Johnson & Johnson had engaged in deceptive marketing.

"Today’s judgment marks the first time a court of law has issued findings of fact and ruled that Johnson & Johnson did indeed engage in illegal false and deceptive business practices," his office said.

It added that between 2008 and 2014, Johnson & Johnson sold more than 470,000 pelvic mesh products across the United States, including 30,000 in California.

Worldwide, more than two million women have had these mesh products implanted in their bodies. 

In addition to the suit filed in California, the company has settled similar claims with the state of Washington for $9.9 million and a coalition of 42 other states for $117 million.

A Johnson & Johnson spokesperson could not be immediately reached for comment but in a statement to The New York Times, the company said it plans to appeal the ruling.