Microsoft is preparing a couple of new Lumia smartphones to serve as Windows 10 flagships - and they've just been leaked online, Digital Spy reports.

The handsets appeared on Twitter under the codenames of Cityman and Talkman - references to classic Nokia phones - posted by reliable tipster Evan Blass.

Both devices are described as "high-end" offerings, with polycarbonate bodies, Qi wireless charging, USB Type-C ports, and Iris scanners.

The Cityman is expected to arrive on the market as the Lumia 950 XL, featuring a 5.7 inch WQHD OLED display, a 64-bit Octa core Snapdragon 810 chip and 3GB of RAM.

Previous reports suggest it will also include 32GB of storage with microSD, a 20-megapixel PureView rear camera with triple LED flash, a 5-megapixel front camera, and a 3300 mAh removable battery.

The Talkman is believed to be the smaller Lumia 950, said to include a 5.2 inch WQHD OLED display, a 64-bit Hexa core Snapdragon 808 chip, 3GB of RAM, 32GB of storage with microSD, a 3000 mAh removable battery, and the same cameras as the larger model.

Microsoft is rumoured to be holding a product launch in October, where its latest phones, tablets and mobile software is expected to debut.