LAS VEGAS, US - Microsoft chief executive Steve Ballmer has announced that a test version of the US software titan's Windows 7 operating system will be available worldwide on Friday.

"We are on track to deliver the best version of Windows ever," Ballmer said while making an opening keynote speech at a premier Consumer Electronics Show in Las Vegas.

"We are putting in all the right ingredients: simplicity, reliability and speed."

Developers and Microsoft partner companies can begin testing Windows 7 immediately, Ballmer said.

"On Friday we will make the beta available worldwide so users can come online and try Windows 7 at home. I encourage you all to go out and download it."

The eagerly-anticipated successor to Microsoft's Vista operating system will streamline everyday tasks, cut boot-up times, extend battery life and make it simple to weave "smart" devices into home networks, Microsoft said.