Apple threatened on Tuesday to remove apps from its widely-used App Store if they don't comply with an upcoming private feature allowing users to block advertisers from tracking them across different applications.
The new feature, dubbed App Tracking Transparency, was initially planned to debut this year, but was delayed to give developers more time to make changes to their apps and address privacy issues.
Some tech companies and advertisers, such as Facebook, have criticised the planned change, saying it could hurt smaller developers such as gaming companies disproportionately.
But Craig Federighi, senior vice president of software engineering at Apple, said users should know when they are being tracked across different apps and websites.
"Early next year, we'll begin requiring all apps that want to do that to obtain their users' explicit permission, and developers who fail to meet that standard can have their apps taken down from the App Store," he said at the European Data Protection and Privacy Conference.
The new feature will require a pop-up notification saying the app "would like permission to track you across apps and websites owned by other companies."
Digital advertising firms expect most users will decline to grant that permission.
"When invasive tracking is your business model, you tend not to welcome transparency and customer choice," Mr Federighi said, rejecting criticism of the new feature.
"We need the world to see those arguments for what they are: a brazen attempt to maintain the privacy-invasive status quo."
Facebook and Google are the largest among thousands of companies that track online consumers to pick up on their habits and interests and serve them relevant ads.
Apple itself was under fire last month when a Austrian privacy group, led by campaigner Max Schrems, filed complaints with data protection watchdogs in Germany and Spain, alleging an online tracking tool used in its devices breached European law. Apple rebutted the charge, calling it "factually inaccurate".
Mr Federighi said the industry would adapt to provide effective advertising without invasive tracking.
"Getting this right will take time, collaboration, listening – and true partnership across the entire technology ecosystem. But we believe the result will be transformative."