Apple has announced a slew of new features coming to the next version of its iOS operating system, iOS 6, at its Worldwide Developers Conference (WWDC) in San Francisco.

The biggest news is that embattled social network Facebook is receiving a big boost in iOS 6, with users to be able to log in once and make posts from the Notification Centre, Siri and Facebook-enabled apps.

Users will also be able to set iOS 6 to automatically update friends' contact details if they change in Facebook, as well as sync events and birthdays in the iOS calendar.

The other major announcement is that Apple's Siri voice assistant, first introduced on the iPhone 4S, will be available on the iPad (latest generation only), and will also offer new features like posting to Facebook and Twitter, smarter sports summaries, the ability to launch apps, and a new ‘eyes free' mode for use while driving.

As expected, Apple has added an all-new Maps app to iOS 6, offering turn-by-turn navigation and photo-realistic 3D views.

What wasn't expected was a new ‘Do Not Disturb' mode, which will prevent the phone from making noise or lighting up if the user receives a call or notification. Users can still make some contacts as important enough to sneak through the DND, and repeated calls will get through as well.

Available in beta for developers and coming as a free download for consumers this Spring, iOS 6 will be offered for most Apple mobile devices, barring it seems the original iPad and any iPod Touch other than the fourth generation.

Apple has promised to post a full video of the WWDC 2012 keynote shortly.