Apple Watch Ultra 2 devices are displayed for sale in Los Angeles
Apple Watch Ultra 2 devices are displayed for sale in Los Angeles AFP

Apple said on Tuesday it will appeal a US import ban on its latest smartwatch models after the Biden administration opted to not veto a ruling on patent infringements.

The ban on Apple's latest smartwatch models came into effect Tuesday, with the Apple Watch Series 9 and Apple Watch Ultra 2 no longer available in stores or online.

The ban is the latest legal tussle involving big tech companies over valuable patents that has also seen Google battle in court against Sonos in a fight over speaker tech.

The United States International Trade Commission (ITC) decided in October to ban the Apple Watch models over a patented technology for detecting blood-oxygen levels.

The order stemmed from a complaint made to the commission in mid-2021 by Masimo Corp, in which the medical device maker accused Apple of infringing on "light-based oximetry functionality."

"After careful consultations, Ambassador (Katherine) Tai decided not to reverse the... determination and the ITC's decision became final on December 26, 2023," the office of the US Trade Representative said in a statement on Tuesday.

Though the US president's office has authority to reverse import bans, such actions are only taken rarely.

In a statement, Masimo said the confirmed ban "is a win for the integrity of the US patent system, and ultimately American consumers who will benefit from an ecosystem that rewards true innovation."

Apple contends that the ITC finding was in error and should be reversed, filing an appeal in a US federal court.

But the company pulled the products from the online Apple Store on December 21, with retail locations ceasing sales December 24 -- just ahead of the holiday.

Masimo contends it invented the technology -- and that Apple poached its employees to win access to the knowledge.

Apple has been steadily ramping up fitness and health features with each generation of its Apple Watch, which dominates the smartwatch category.

In September, Apple released the Apple Watch Series 9, touting increased performance along with features such as the ability to access and log health data.

"We strongly disagree with the USITC decision and resulting exclusion order, and are taking all measures to return Apple Watch Series 9 and Apple Watch Ultra 2 to customers in the US as soon as possible," Apple said in a statement Tuesday.

At the time of the original decision, Apple said Masimo had "wrongly attempted to use the ITC to keep a potentially lifesaving product from millions of US consumers while making way for their own watch that copies Apple."

In May, a trial of Masimo's allegations ended in a mistrial after jurors failed to reach a unanimous verdict.

Apple has argued that Masimo is using litigation to make way for its own Apple Watch-inspired products.

In November, Masimo was cleared by US regulators to use its own wrist-worn product for prescription and over-the-counter use.

Late last year, Apple filed two patent infringement lawsuits accusing Masimo of copying Apple Watch technology.