Joint venture developers Arlington Real Estate and the Richardson family now hope to start building work on the £150m scheme in the first quarter of next year.
They are in the final stages of selecting a construction partner, with tenders due back in November and a contractor due to be named in the early next year.
Now 70% of the project will be completed in the first phase, expected to finish in 2021.
As a result of improvements, phase one will contain a greater mix of uses featuring 153 apartments, a 92-bed, flagship Premier Inn hotel, and 55,000 sq ft of offices, which will support up to 500 new jobs.
The homes, offices and hotel will be joined by cinema operator Everyman, which made its first commitment to the North East with an agreement to open a boutique cinema at Milburngate, together with bar and restaurants, Pitcher & Piano, Bar + Block and Miller and Carter.
Around 85% of the public space will be completed in phase one, helping to better link the railway station, riverside and city centre.
Ben Holmes, Director at Richardsons, said: “The updated designs for the first part of Milburngate, which include important feedback from local stakeholders, reflect the synergies we aimed to achieve across the whole development.
“Delivering elements of the development earlier than originally planned, to complete 70% of the entire project, will support Milburngate’s position as a catalyst for job creation and a magnet for leisure visitors looking for a premium and unique experience unavailable at other locations in the North East.”