Apple's new iPhone device will raise the bar on mobile device usability, according to Gartner research director, Robin Simpson.

The device, due for release on Friday in the US and sometime in 2008 in Australia, features a unique touchpad interface and motion sensor technology - combining a traditional mobile phone with a music player and handheld Web and email browser.

Based on the original demonstrations he saw at MacWorld, Simpson said the iPhone was a "step-change" in terms of ease of use.

"Consumers are going to want to use touch screens and sensors, they are going to expect more sophisticated graphics," he said. "The iPhone will reset the bar - it really is that different."

Simpson, normally quite reserved when it comes to over-hyped products, said Apple's ability to make things simple would have repercussions for handset manufacturers and users globally.

Mobile phone manufacturers have to date been continually loading new functionality onto their devices to fight price erosion - but much of this functionality is lost on the average consumer, who is more concerned with usability and design.

If judged only on its bells and whistles, the iPhone doesn't rate that well. The GSM device features Wi-Fi but no support for 3G networks, has a 2 megapixel digital camera in an era of 5 megapixel cameras, has a far smaller capacity for music storage than higher-model iPods, and boasts no integrated GPS.

"In terms of extra features, you'd even say it's ordinary," Simpson said. "It might be the right product for the US, but not having 3G is very disappointing for people in Australia and Europe."

Simpson hesitated to guess whether Apple would add 3G when it brings the product to the rest of the globe - but was confident the device will change significantly between releases.

"Every nine months or so we got a new model of the iPod with added functionality," he said.

It is the integration of touch and gesture that has Simpson convinced of the iPhone's ability to shake up the handset market.

Motion and proximity sensors have proved very popular in gaming. The technology is featured in Nintendo's Wii gaming system, which this week became the fastest gaming console to reach 100,000 sales.

The iPhone's proximity sensors are concerned with ease of use. When users hold the device up to their face to make or take a call, the touch screen turns itself off so that the user can't accidentally press buttons on the screen while speaking into the device. The display can also sense whether the user is holding the device in portrait or landscape, and the interface automatically shifts accordingly.

"It's a great example of contextual computing - where the computer knows so much about your environment, it makes decisions for you," Simpson said. "I really do believe that this could be a tipping point for human-computer interface design."

Simpson said he discussed these new features with Gartner's semi-conductor analysts, and collectively they had adjusted the analyst group's semi-conductor forecasts for mobile devices to reflect the iPhone's strength.

The variable that remained, he said, was whether people would pay a premium for usability. The iPhone will retail in the US for $US499 and $US599 for the 4GB and 8GB models, respectively.

"Consumers are unaccustomed to paying this much for a phone," he said. "Apple enthusiasts will buy it regardless - but the real test will be six months on when the rest of the market looks at it.

"When the iPod came out, a lot of people damned it as too expensive. Their minds only changed due to the ecosystem, such as iTunes, that came with it. That ecosystem, to a large degree, is already in place for the iPhone."