Tablets, smartphones and wearable tech bought for Christmas could increase the risk of firms being hacked, according to Ernst & Young (EY).

Workers returning after the December break may wish to use their new devices as part of their job, yet a lack of spending around bring your own device (BYOD) policies could leave the gadgets open to hackers.

Massimo Cotrozzi, director of cybercrime investigations at EY, said "We are only in the first few days of 2015, but we are already seeing issues with companies leaving themselves exposed to this phenomenon."

"The new smart mobile/tablet and wearable tech that employees bring into the office could be now connecting via the corporate wireless networks to external cloud systems which, in the best case, have not been appropriately protected, let alone tested."

"Organisations that are unprepared could be caught napping while hackers are getting in, using employee devices, via the back door."

84% of companies worldwide consider mobile security a medium or high priority, according to figures from EY, yet only two-fifths are planning on increasing spending to cover the threat posed by BYOD.

"Businesses also need to be prepared for when the worst occurs and have a clear strategy to respond to and clean up after an attack," Cotrozzi added.

"Employees must understand how to preserve evidence left by the perpetrators and must also establish contingencies to deliver an instant response to reassure customers and prevent reputational damage."