Apple is offering a $US1 million reward to anyone who can pull off a specific iPhone hack.

Apple has expanded its bug-bounty program to include a new million-dollar reward for anyone who can pull off a zero-click full chain kernel execution attack with persistence.

The requires accessing the core of Apple’s iOS operating system and gaining control of an iPhone in a way that would not require any user interaction.

Reports say it is the biggest bug-bounty reward offered by a major technology company. Those who can spot a vulnerability in a beta version of Apple’s software are eligible for a 50 per cent bonus.

Apple announced the expanded bug-bounty program during a Black Hat cybersecurity conference in Las Vegas alongside a string of other critical updates.

In addition to the new $US1 million reward, Apple is also offering new bounties on platforms such as macOS, tvOS, and watchOS, the software that powers its Mac, Apple TV, and Apple Watch products.

The company has also opened the scheme to all researchers who wish to participate.