"A Samsung TV will be able to listen, see and do what it wants, without even touching a remote control," said B.K. Yoon, president of Samsung's consumer electronics division.
Saying "Hi TV" turns on voice control, "web browser" takes users online, and selections and functions such as increasing the volume can be carried out with a wave of the hand.
Rival South Korean manufacturer LG unveiled smart TVs with a simplified interface and said it was adding voice and gesture recognition capabilities to an existing "magic wand" motion controller for its TVs.
"We're very impressed with the accuracy of our voice recognition," Tim Alessi, LG's US director of new product development, told the Financial Times. "It's come a long way in recent times and we think it will be well received."
LG also showed off a Google TV feature on some of its devices. Google launched a simplified version of its "TV meets the web" operating system and interface late last year. The original version was criticised for its complexity and failed to take off with devices made by early adopters Sony and Logitech.
"I see 2012 as the year of the interface," Shawn Dubravac, research director of the Consumer Electronics Association, told a news conference on Sunday.
Showing slides of the first remote control, with just four buttons, and the latest with more than 40, he said manufacturers had introduced too much complexity for consumers, but were simplifying the user experience with voice and gesture recognition being added.
Many analysts expect Apple to introduce its first television in the near future, with voice recognition similar to the Siri personal assistant on its iPhone 4S likely to be incorporated.
Lenovo unveiled its K91 Smart TV, the first to be based on the latest Android 4.0 operating system from Google. As well as voice recognition, the TV's built-in 5 Megapixel webcam can use facial recognition to control viewing and enable advanced parental control.
Other TV trends revealed by manufacturers at CES included thinner bezels, better link-ups with tablets and smartphones and 55in OLED displays that offer industry-leading picture quality but have proved to be hard to manufacture in large sizes.
LG announced it had developed its own Arm-based processor for its Smart TV, the L9, rather than relying on traditional processor makers. Intel recently announced the dissolution of its digital home division and has left this market to chips based on designs by the UK's Arm.
However, LG said it would be the first TV maker to integrate Intel's Wi-Di â€“ a technology that allows laptop owners to share wirelessly what is on their screens with bigger TV displays.