The US Supreme Court on Monday declined to consider an appeal by Facebook that would have derailed a $15 billion lawsuit over whether it illegally tracked users about a decade ago.

The nation's top court issued an order denying a request by the leading social network to review a California federal court's decision to allow the litigation accusing Facebook of violating wiretap laws.

Facebook did not respond to a request for comment.

It had argued in court filings that it was a legitimate "party" for exchanges involving digital content received from software tools such as "like" or "share" buttons plugged into other websites.

"Rather than eavesdropping on a separate communication, the communication with Facebook contained distinct content intended for Facebook," the leading social network said in a legal filing.

US wiretap law makes it illegal to snoop on electronic communications unless one is a party to the exchange.

The suit accuses Facebook of wrongly tracking users away from the social network, then making money from the data by selling it to marketers for targeting ads.

The class action lawsuit consolidated more than 20 related cases filed in an array of US states in 2011 and early 2012 and seeks more than $15 billion on behalf of members of the world's largest social network.

Facebook has since changed the way it uses software snippets such as like and share buttons that gather information about users' internet activities.

The Silicon Valley tech giant added that allowing the case to proceed would have "sweeping, and detrimental consequences."

Critics and regulators have repeatedly taken aim at Facebook over user privacy.