Stone & Chalk will be located on level 2 of 50 Bridge Street, with 2,300 square metres of 'agile office space' – almost double that of the original plan.
The new fintech hub, launched by NSW Premier Mike Baird earlier this year, was originally intended to be housed at 45 Clarence Street.
Stone & Chalk chief executive Alex Scandurra said no one involved in the project expected the "overwhelming demand" from the 350 fintech entrepreneurs applying for the 150 places initially on offer.
"Our primary aim is to facilitate and promote the development of a world-leading fintech start-up community in Australia, and given the high volume of start-up applications, we felt that we needed to accommodate a larger number of entrepreneurs from day one," Mr Scandurra said.
"It's an incredibly high-class problem for us to have. We're very excited about our new Bridge Street solution, which has been endorsed by all stakeholders."
Mr Scandurra said he was still aiming to open Stone & Chalk in July.
"We are a start-up ourselves and are simultaneously building our own team, hub and proposition. We are also trying to review all the applications as best as we can and ask everyone to hang in there with us!" he said.
The larger Bridge Street premises will now accommodate up to 200 entrepreneurs through a combination of dedicated labs, full and part-time desks, secure offices and casual 'drop in' spaces.