Apple has introduced its new mobile operating system, iOS 9, with enhanced Siri features and security improvements.

iOS 9 can be used on iPhone, iPad and iPod touch. It will be available as public beta next month and be available as a free update this Autumn.

The new multitasking features designed particularly for iPad will enable users to work with two apps at a time, side-by-side or with the new picture-in-picture feature.

An important feature in the new Siri is enhanced intelligence while other enhancements include contextual reminders and new ways to search photos and videos.

The new slide over feature in iPad allows uesrs to work simultaneously in a second app without leaving the first.

Maps adds support for metropolitan transit systems and schedules in iOS 9. The company said the News app combines the design of a print magazine with the interactivity of digital media.

The new OS offers a typical user with a further hour of battery life and a low-power mode. Improved security features strengthen the passcode to protect users devices and enhance two-factor authentication by building it directly into iOS.

Apple senior vice president of software engineering Craig Federighi said: "iOS 9 is packed with more intelligence throughout, and delivers big updates to the apps customers use most — Maps supports public transit, a redesigned Notes app provides great new ways to capture ideas, and a beautiful News app delivers content that’s personalized to your interests.

"With our new iPad features, users can take advantage of the power of iPad, working in two apps at the same time with Split View, Slide Over or Picture-in-Picture."