Atlassian will build a $1 billion-plus concrete-and-timber tower next to Sydney's Central Station, as the flagship project in a NSW government-backed technology precinct that will eventually link Ultimo with Redfern on the CBD's southern edge.

The tech giant has chosen, but not publicly announced, a design by New York-based SHoP Architects and Australia's BVN for the 180-metre tower that will be the highest timber structure to date in this country and will form a key part of Atlassian's stated plan of achieving net zero carbon emissions by 2050.