Sony has unveiled three new Xperia smartphones - including a larger version designed to take on the iPhone 6 Plus.

The technology giant used its press conference at IFA in Berlin to confirm the new Xperia Z5, as well as Compact version - something the firm has done in previous generations - as well as the phablet-sized Z5 Premium, which Sony says is the "world's first 4K smartphone".

The larger screen on the Premium - 5.5 inches; the same as the iPhone 6 Plus - can display ultra HD, and also has the technology built into it that can upscale HD content into 4K, Sony says.

The new line of devices is also marked by the introduction of a redesigned camera, which has a 23 megapixel lens, as well as what Sony claims is the fastest autofocus ever in a smartphone; 0.03 seconds.

Hiroki Totoki, president of Sony Mobile said: "Smartphones are part of people's lives.

"Since users already create, share and enjoy most of their content on the go, we've set out to bring Sony's latest innovations in camera, design and display to ensure the Xperia Z5 series is the best possible lifestyle and entertainment platform."

The complete redesign of the camera in each of the phones involved taking technology from the firm's own full-size camera range.

The new line also comes with a fingerprint scanner built into the power button, which sits on the side of Xperia smartphones. The move follows the likes of Apple and Samsung in introducing biometric security to a mobile device.

Another trend Sony is embracing is the colour gold, which the larger Premium has as a colour option when the device goes on sale in November, with the Z5 and Z5 Compact launching in October, the company confirmed.