Apple is targeting distracted motorists with a new feature that will automatically block incoming iPhone notifications while you drive.

The Do Not Disturb While Driving function is a part of the iOS 11 operating system, revealed at Apple's Worldwide Developers Conference in San Jose, California yesterday.

Users can choose to turn on the feature, which would then automatically withhold alerts and notifications when the phone senses it is in a moving vehicle.

"When you finish that first drive we're going to suggest, 'hey how about we activate do not disturb while driving?'," said Apple's senior vice president of software engineering Craig Federighi during the keynote.

"And when we do, instead of seeing all those notifications, we have this new user interface for you."

The slideshow behind him showed an iPhone with a black screen.

While it is illegal to use a mobile phone while driving in most countries, statistics show an increasing number of motorists admit to using one anyway, exposing them to heightened risk of accidents.

The feature may prove popular with drivers who want help blocking out these distractions. In addition to blocking notifications, it gives users the option of sending an auto-reply to contacts listed in their favourites to explain their delayed response.

Do Not Disturb While Driving uses either a Bluetooth car connection or the Doppler effect over Wi-Fi to know when the device is in a moving vehicle.

Other features of iOS 11 include a new augmented-reality platform, ARKit, for developers to build experiences based on the iPhone camera.

Updates to Siri will make the voice assistant more powerful, integrating machine learning to provide more personalised information to users.

The big hardware announcement from yesterday's event was the arrival of Apple's smart speaker, Homepod, a rival to the Amazon Echo and Google Home. The Apple Worldwide Developers Conference continues until 9 June 2017.