The design is in "the preliminary stage", and construction is set to start early next year, the health organisation says.
National Dunedin list MP Michael Woodhouse said the lack of a design could put the building’s new 2029 completion date "severely at risk", a claim HNZ denies.
The inpatient building had been set to open in 2028, but the date was pushed back when the Government announced design cutbacks to the value of $90million last December.
The changes — including the loss of 12 beds, two operating theatres and two scanners — were announced along with a grant of $110million, to address a projected budget blowout of $200million.
Mr Woodhouse said the lack of a design at this stage was disappointing, and offered little certainty about the savings the cuts aimed to make.
"The biggest cost pressure on this project is delay," the former chief executive of Mercy Hospital, in Dunedin, said.
The inpatient building — stage two of the new hospital build — was supposed to follow the completion of stage one, the outpatient build, but Mr Woodhouse questioned how this would be possible without pushing out the completion date.
"They have to get out and tender stage two of the project as soon as possible, otherwise all of the pandering about design changes and cost savings is academic, because they’re probably going to have to go through it all over again."
HNZ delivery of infrastructure and investment group director Monique Fouwler said the inpatient building was expected to be completed in 2029, while the outpatient building would be completed in late 2025.
"The main contractor for the delivery phase of the inpatient building will be confirmed this year," she said.
A design incorporating the changes was in development.
She did not say when it would be complete, but said it would be delivered in stages so construction could begin early next year.
"It is largely similar to the previous design but altered to be more efficient in layout."
It would be larger, although the dimensions were unavailable.
HNZ could not say how many non-clinical spaces had been lost, as layout of individual spaces was not finalised, but estimated a floor area reduction of 5.6%.
It could not say what percentage would be shell space (space designated for a future use) in addition to this.
"As we continue the design process, we will refine the design of the inpatient building, including its exact dimensions and systems, and finalise the changes that have been made."
The next step was developed design and then detailed design, she said.
