Tech giants Apple, Google, Adobe and Intel settled a lawsuit Thursday that charged they had colluded to hold salaries down by agreeing to not poach each other's staff.

The four reached an agreement to settle all claims against them with lawyers for the plaintiffs in the case dating back to 2011, a statement from the San Francisco US district court said.

No details were given of the amounts, if any, that the four will pay to hundreds or thousands of workers covered under the class-action suit to resolve the case.

The original lawsuit alleged that senior executives of the tech giants "entered into an interconnected web of express agreements to eliminate competition among them for skilled labor."

The conspiracy allegedly involved agreements not to recruit each other's employees, to notify each other when making an offer to another's employee, and, when seeing an employee in negotiations with one company, not to make a counter-offer to the employee.

"The intended and actual effect of these agreements was to fix and suppress employee compensation, and to impose unlawful restrictions on employee mobility," the suit said.

Three other companies originally named in the suit, Intuit, Lucasfilm and Pixar, settled their cases last July for a collective $20 million.

That settlement noted that they accounted for less than eight percent of all those covered in the class-action suit, suggesting that Thursday's settlement by the four others could be much higher.

The case said that Pixar and Lucasfilm were the first to make secret pacts to suppress worker pay and mobility, when late Apple founder Steve Jobs was head of Pixar in 2005-2006.

Shortly after that deal was set, Jobs took Apple into a no-poach deal with Adobe, the software company, according to the suit.

The case against the remaining four companies in the suit gained strength in January when the judge in the case, Lucy Koh, cited emails from Jobs requesting in 2007 that Google stop recruiting Apple workers.