On Tuesday, the French watchdog which governs radio frequencies also told the tech giant to fix existing phones.
The ANFR has advised Apple that if it cannot resolve the issue via a software update, it must recall every iPhone 12 ever sold in the country.
But the World Health Organization has previously sought to allay fears about radiation emitted by mobile phones.
It says on its website there is no evidence to conclude that exposure to low level electromagnetic fields is harmful to humans.
The iPhone 12 was first released in September 2020, and it is still sold worldwide.
Apple told the BBC it was contesting the ANFR’s review, and said it had provided the regulator with lab results from the tech giant itself and third parties which show the device is compliant with all the relevant rules.
It said the iPhone 12 was recognised as being compliant with regulations on radiation levels worldwide.