Andy Rubin, Google's vice president of mobile, says Microsoft made a bold move with its Metro user interface.

Google’s head of mobile, Andy Rubin, said Tuesday that Microsoft’s Metro user interface is a bold move that could prove problematic for the company.

“From my taste and my perspective, it could be very dangerous for Microsoft,” he told journalist Walt Mossberg at an AllThingsD conference in Asia.

Rubin said because Microsoft was behind in the mobile market, it innovated “on a different axis” with the Metro UI for Windows Phone 7. However, the operating system leaves less room for creativity and for software and hardware makers to express themselves, he said, hinting that Microsoft could run into trouble with manufacturing partners.

“If you want to take over the screen, you should be able to take over the screen,” Rubin said.

In contrast, Rubin said the Android operating system is an open one that customers can adapt to their own purposes. Amazon recently did so with its new Kindle Fire tablet, hiding the Android OS under its own interface, which Rubin said is “fine for Google.”

“I don’t view this as some kind of walled garden,” he said.

Microsoft has integrated the Metro user interface into its upcoming Windows 8 operating system. The interface was developed for touch-based devices, including tablets, but will be “equally at home” with a mouse and keyboard for a PC, according to Microsoft.

Rubin’s comments came the same day that Microsoft CEO Steve Ballmer took a swipe at Android, saying customers need to be computer scientists to use an Android phone.

The two companies are rivals in the mobile space, though Google is miles ahead with 43 percent of the smartphone market, compared with Microsoft’s 5 percent, according to recent comScore data.