Voice commands don't always work very well on the Xbox One, but maybe Amazon can succeed where Microsoft has floundered?

The bookseller has introduced something called the Amazon Echo, a Bluetooth-enabled speaker with an always-on microphone that listens for voice commands.

The Echo can play music or the news, answer questions, create lists, set alarms, and more at your command, according to Amazon.

And the trigger word that prompts it to start listening is "Alexa."

It may not be ideal for people named Alexa, but Amazon says the Echo can hear you even when it's playing music from its speaker.

A 9-inch cylinder, the Amazon Echo has a built-in subwoofer and reflex port, a light around the top, an "action" button, and a button to mute the microphone.

A companion app for Android and Fire phones, plus a browser app for other devices, helps with initial set-up and further management of the Echo.

And Amazon says the Echo will harness the cloud to constantly learn and get smarter.

The Amazon Echo is available to purchase by invite only for $199 (about £125, AU$230) or $99 (about £60, AU$115) for Amazon Prime subscribers.