Models manufactured through March 2013 may be affected by this issue.
Apple has admitted that a small percentage of its iPhone 5 models has developed minor faults, and offered to rectify the problem.
The technology firm revealed that the on-off buttons, which also control the sleep/wake function, are faulty on few of its iPhone 5 models, sometimes ceasing to function or working intermittently.
It believes that the iPhone 5 models manufactured through March 2013 may be affected by this issue, but is unsure how many were shipped with the faulty switches.
iPhone customers can claim the service free of charge for models that exhibit this issue and have a qualifying serial number.
Apple requested the iPhone owners' type in their serial numbers on the company's website to determine if their phones qualify for a fix, afterg which they can take their gadgets to a store or mail them to the company for repairs.
Apple rarely initiates large-scale repair programmes for its products, but in 2010 iPhone 4 models experienced signal loss when handled a certain way.
The technology firm later admitted the fault and subsequently offered free phone casings to correct the issue, which went on to become popular as Antennagate.