The new iPhone 6s and 6s Plus hit stores on Friday, with dozens of people - and a robot - lining up in Sydney to kick off a global sales cycle that will be scrutinized for signs of how much juice Apple Inc's marquee product has left.

Analysts expect 12 million to 13 million phones to fly off the shelves in the first weekend, up from more than 10 million last year when the hugely successful iPhone 6's launch was delayed in China, the world's biggest smartphone market.

Among the first to pick up the new iPhone 6s in a cold, rainy Sydney was a telepresence robot named Lucy, operated by marketing executive Lucy Kelly.