March 25 (Reuters) - Apple ( AAPL ) has been hit with a

flurry of new consumer lawsuits accusing the iPhone maker of

monopolizing the smartphone market, piggybacking on a sweeping

antitrust case lodged by the U.S. Justice Department and 15

states last week.

At least three proposed class actions have been filed since

Friday in California and New Jersey federal courts by iPhone

owners who claim Apple ( AAPL ) inflated the cost of its products through

anticompetitive conduct.

The lawsuits, seeking to represent millions of consumers,

mirror the Justice Department's claims that Apple ( AAPL ) violated U.S.

antitrust law by suppressing technology for messaging apps,

digital wallets and other items that would have increased

competition in the market for smartphones.

Apple ( AAPL ) has denied the government's allegations. The

Cupertino, California-based company did not immediately respond

to a request for comment on the consumer lawsuits.

Attorney Steve Berman, whose law firm Hagens Berman Sobol

Shapiro filed one of the new cases, noted that his firm had

earlier sued Apple ( AAPL ) for allegedly thwarting competition for its

Apple Pay mobile wallet.

"We are pleased that the DOJ (Department of Justice) agrees

with our approach," Berman said.

Attorneys behind the other new cases did not immediately

respond to requests for comment.

Apple ( AAPL ) is already fighting private lawsuits challenging its

business practices as anticompetitive. A judge in February ruled

that Apple ( AAPL ) must face a class action on behalf of millions of

consumers claiming it monopolized the market for iPhone apps.

Apple ( AAPL ) denies the claims.

Hagens Berman previously secured a combined $550 million

in settlements from Apple ( AAPL ) in separate cases related to its ebook

pricing and app store policies.

A 2022 study by a University of Buffalo law school professor

found that private antitrust class actions can sometimes go

farther than government cases, expanding "the scope of

wrongdoing, the amount of recovery, or the number of defendants

involved."