Apple has embarked on a hiring spree to tackle design problems with its “iWatch” wrist computer, bringing in fresh expertise amid concern that the launch of its first new product since the death of Steve Jobs could be at least a year away.

The company has begun hiring “aggressively” for the project in recent weeks, say people familiar with Apple’s plans for the wearable device, a move which shows it has stepped up development but which raises questions over the ability of its own engineers to develop wearable technology.

As Apple moves from iPods, iPhones and iPads into an entirely new category of product, it is looking beyond its existing staff in Cupertino for the talent required to build it – an indication that the endeavour involves “hard engineering problems that they’ve not been able to solve”, according to one source.