Dr John Chambers, who retired last year after 30 years working in ED, said the proposed changes were crazy.
"The numbers of cubicles in ED and operating theatres as developed in the original plans were not plucked out of thin air.
"They were the result of years of meetings, consultants’ reports and projections to meet the needs of our population from 2030. With the proposed cuts, the ED will be overloaded within a week of opening."
He made his comments after revelations Health New Zealand Te Whatu Ora (HNZ) is considering cuts to the inpatients building project, which would affect the level of care provided to patients.
The cuts being looked at by HNZ include the "shelling" of an 11-bed "short stay" pod in the emergency department and instead incorporating these beds in acute wards.
The organisation is also looking at downgrading operating theatres, by having only one with specialist-grade ventilation instead of two, removing wall-mounted medical gas in some theatres and having only one high-spec "hybrid theatre" on opening, instead of two.
"When cuts like this are made, you’re undermining the entire system as it stands.
"Our population is only going to get bigger, and with that more beds and services will be needed."
Meanwhile, several Dunedin councillors said they were ready to revive the They Save — We Pay campaign.
Cr Steve Walker said his campaign T-shirt was "washed, ironed and ready to go into battle".
Cr Sophie Barker said the council should hold immediate talks with the Minister of Health and "ensure the government delivers on the promised hospital, with no cuts".
Cr David Benson-Pope said none of the proposed changes made sense.
"Time for a new campaign, I think, and a much more aggressive one at that."
Cr Christine Garey said any of the proposed changes would amount to "cutting corners", which was of "real concern".
"I would imagine we are on the cusp of a new campaign."
Cr Jim O’Malley said the revelations were indicative of "how badly Health NZ has handled the project from the start".
Cr Andrew Whiley said a very clear plan and timeline was desperately needed from the government.
"This is an extremely important project for the city and the region.
"We are paying the price from the previous Labour government wanting to redesign the hospital and potentially save dollars. Any potential savings have definitely been lost and if they had stayed the course with the original plans we would be seeing two nice buildings and 800+ workers over the two sites."
Asked about the possibility of reviving the campaign, Dunedin Mayor Jules Radich told the ODT "at this stage, more information is required before the campaign is reignited".
"Many previous cuts have been discussed at government level, but always sensibility has prevailed, because this project has been well thought out over many years by the appropriate experts, especially the clinicians."
Dunedin MP Rachel Brooking said she was disappointed, but not surprised by the revelations.
"Health Minister Dr Shane Reti has been hiding behind his officials for far too long. He must direct Health New Zealand to deliver Dunedin hospital as was planned, and as he promised.
"If he has changed his position, he should front up to the people of Dunedin and the wider southern region."
Taieri MP Ingrid Leary said communities in Taieri and Invercargill had some of the least access to timely health services in the country, and the news of more cuts and more delays to the new hospital would "only increase their anxiety and frustration".
A spokeswoman for Health Minister Dr Shane Reti said the minister had "always acknowledged that there are many challenges with the new Dunedin hospital".
"The recent revelations about the dire state of Health New Zealand’s finances means that now more than ever, we need to ensure every public dollar available to health is spent wisely."