After receiving reports from iPhone 5s owners about battery life issues, Apple has confirmed that a small number of handsets have shorter battery life than advertised, due to manufacturing defects. The manufacturer promised to call affected iPhone owners and arrange for a free replacement.

The exact number of affected consumers was not revealed but there are speculations that it could be in the low thousands since the company will personally call the owners of affected devices. During the initial roll out of the iPhone 5s in September, the company has sold around nine million units in the United States, China, and other countries, and it is believed only a small fraction of these have battery issues.

"We recently discovered a manufacturing issue affecting a very limited number of iPhone 5S devices that could cause the battery to take longer to charge or result in reduced battery life. We are reaching out to customers with affected phones and will provide them with a replacement phone," said Apple spokesperson Teresa Brewer in an interview. 

One of the biggest selling points of the new iPhone is its longer battery life that is said to last for 250 hours on standby and around 10 hours with average use. The batteries of the iPhone 5s are manufactured by Sony.

Consumers have reported through Apple forums, problems about the battery of the iPhone 5s prior to the confirmation by the manufacturer.

"I bought iphone 5-s on 25 October . I restored my phone from icloud backup but i noticed that my phone battery is draining so quickly even less than or [similar] to its predecessor iphone 5," said one user.

"I've noticed that my battery can easily drain 5-10% if I use it moderately for a few minutes. Also, sitting in standby, it drains battery more than my 2.5 year old iPhone 4 did!  I've turned off anything that can update in the background.  Not sure what else to do at this point," another user wrote.

Consumers who think they own a defective iPhone but have not received a call from Apple yet, may contact AppleCare to check. Affected consumers may then make an appointment to get a replacement phone through a local reseller.

Apple iPhone 5s owners may also opt to receive their replacement unit via courier. The company will send a packet for return shipment.

Defective batteries issues are not new to Apple. In 2006, the company had recalled laptops due to problematic batteries, which were also manufactured by Sony.