Apple is aiming to have its next big thing on wrists in China, the US and beyond within weeks.
The tech giant says the Apple Watch will be available in nine countries, including Australia, from April 24 at a starting price of $US349 ($A452).
"Apple Watch begins a new chapter in the way we relate to technology," said chief executive Tim Cook at an Apple Watch media event in San Francisco on Monday.
Cook said "the most personal device we have ever created" features a variety of displays ranging from a classic watch face to an animated Mickey Mouse.
Connecting wirelessly to a user's iPhone, the watch is designed as a wrist device for messaging, calls and numerous apps, especially those geared toward health or fitness.
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Users can send a real-time display of their heartbeat to another Apple Watch to "let someone know you are thinking about them".
Apple enters a market that has a number of players from South Korean giants Samsung and LG, to Japan's Sony and startups such as Pebble.
But analysts expect Apple to invigorate the landscape by integrating the watch with the iPhone and its software ecosystem.
"Apple will outsell all the rest of them combined in 2015," said Forrester analyst James McQuivey.
"But in so doing, Apple will bring very valuable attention to the market, essentially releasing a rising tide that will float all their boats."
Apple Watch can be used as a sort of wrist-radio featuring a built-in speaker and microphone.
It is integrated with Apple Pay's mobile wallet and can also be used to view pictures, monitor news and connect to social media.
Apple said the ranks of businesses accepting Apple Pay is booming and that it recently sold its 700 millionth iPhone.
"Now it's on your wrist, not in your pocket or your pocketbook," Cook said.
Apple demonstrated using the watch to find out lyrics to songs being heard, remotely opening home doors and displaying barcodes that act as airline boarding passes.
But a key focus was health and fitness applications.
The watch has an accelerometer, a heart rate sensor and sensors for "a comprehensive picture of your all-day activity and workouts."
It will prompt a user to get up and walk if sedentary too long.
Cook boasted the device will have a battery life of about 18 hours.
Entry price will be $US349 in the United States, with the price climbing through three style categories, the top being the $US10,000 luxury gold model.
Initially, it will be available in Australia, Britain, Canada, China, France, Germany, Hong Kong, Japan and the United States. Pre-orders will be taken from April 10.
Jan Dawson at Jackdaw Research said he expects Apple to sell about 20 million of the devices this year, which will "catalyse the overall smartwatch market and help other vendors even as Apple comes to enjoy levels of market share it hasn't had since the iPod."
