The Finnish firm recently posted quarterly losses for its smartphone division, but is said to have raked in around £370 million in royalties from the Cupertino-based firm.
Apple has an extensive licensing agreement in place with Nokia, using its patents in products such as the iPhone 4S, meaning that the iOS device generates more income for the firm than its own Lumia phones.
Nokia previously launched the Lumia 800 and Lumia 710 Windows-powered handsets, and is hoping to reverse its fortunes with the newly-released Lumia 900, and the budget-friendly Lumia 610.
AppleInsider speculates that Nokia could withdraw from the product market altogether if the slump continues, or sell its entire patent library to another company in a lucrative deal.
Motorola Mobility adopted the latter strategy when it agreed to sell its patent portfolio to Google in a $12.5bn (£7.9bn) deal.