Apple Inc is expected to take the wraps off a faster 4G-equipped iPad on Wednesday, hoping the latest version of its tablet can safeguard its dominance as rivals from Amazon to Samsung pile into the market.

CEO Tim Cook, presiding over his biggest product launch since 2011's voice-enabled iPhone 4S, has so far not introduced the highly anticipated third iteration of the tablet, which commands upwards of two-thirds of the growing market.

Cook kicked off Wednesday's event again holding forth on what he called a post-PC world, in which users move increasingly away from traditional desktop and laptop computing and toward an array of portable devices.

And he announced that the company's new $99 Apple TV set-top box, a concept that late CEO Steve Jobs had called a hobby, now supports high-definition 1080p screen technology.

Last year alone we sold 172 million post-PC devices, Cook told the audience at the Yerba Buena Center in downtown San Francisco, Apple's preferred venue for product unveilings.

And this made up 76 percent of our revenues. This is incredible.

The company tends to reserve the most anticipated details - including pricing - for towards the end of its tightly scripted launches. The latest iPad is expected to sport 4G or faster wireless technology, a quicker processor and better screen.

(Reporting By Poornima Gupta and Alexei Oreskovic; Editing by Tim Dobbyn)