The Glass Snail? The Pencil Sharpener? The New Toaster? The latest addition to Sydney's hotel boom is set to get the city's armchair architects talking.

Wedged between two expressways and overlooking Darling Harbour, the under-construction building at the gateway to the CBD has been picked by the world's largest hotel group, Marriott International, as the third site of its luxury W Hotel chain.

Known as The Ribbon, it sits on the former site of the IMAX theatre within the western distributor and is part of a $730 million redevelopment.

Artist's impression of the Ribbon W Hotel being constructed at Darling Harbour.

Having been stagnant for close to 18 years, Sydney's hotel sector has seen a burst of activity of late, with four new high-end projects under way around the Darling Harbour precinct.