Doma Group, which built the interchange below a multi-level car park that will ultimately be used by tenants of adjoining 30-storey towers, handed the site to the NSW government last week.

Workers have been on site for almost two years, spending about a year demolishing the Store building and remediating land before beginning construction on the combined interchange-car park development last July.

The project is drawing to an end with scaffolding around the rustic-looking car park set to be removed next month.

The 678-space car park is not expected to open until late July, but the ground-level bus interchange will be operational before then.

The Newcastle Herald visited the construction site on Friday.

The large open-space bus interchange has a long stretch of passenger pick-up and drop-off points on its northern edge parallel to the adjacent train station, and bus layover spaces in the centre and on the southern side.

Drivers' facilities and a passenger waiting room are located at the western end, while a thoroughfare at the eastern end will allow safe passage to the Newcastle Interchange light rail stop and train station entry gates.

Transport for NSW refused to confirm an opening date for the interchange on Friday, but the Herald understands it will be ready at the end of this month.

How the interchange will be incorporated into the Newcastle Transport bus network should become clearer in coming weeks as public transport operators are required to provide at least a fortnight's notice of any timetable changes.

Asked how the interchange would alter the city's existing bus network, a TfNSW spokesman said there would be "minimal" changes.

Multiple Newcastle Transport buses pass by the interchange, stopping nearby on Hunter Street, but only bus route 22 terminates in the immediate area.

"The new bus interchange will be used by local and regional bus service operators, coaches and periodically for rail replacement services," a TfNSW spokesman said.

"We expect around 300 buses to utilise the interchange on a weekly basis from commencement."

The five-level car park sits on V-shaped concrete pillars above the bus interchange.

Vehicles will enter and exit both the interchange and car park via Hunter Street opposite the Cambridge Hotel.

Ramps provide access to the car park, which is set to be opened to the public as a paid parking operation until planned 30-storey towers are built next door. It would then be used by residents and workers only.

The Herald reported in March that Wilson Parking would operate the car park.

Doma Group is also building an 12-storey commercial building between the car park and Stewart Avenue.