"Dunajtschik has said his philosophy is that people are blessed with a sound mind and body can look after themselves, but those born with or suffering illness and disability need our support."
Coleman said Dunajtschik, aged in his 80s, had been a substantial benefactor in health, sport and education for 40 years, but this donation was unparalleled.
The new hospital is expected to be around 7000 sq m and is likely to comprise three floors and include 50 inpatient hospital beds. It will be built in the Wellington Region Hospital campus, and construction is expected to begin early next year and take about 18 months.
Abound 4000 children are admitted to child health services at Wellington Regional Hospital each year, and more than 5000 children who attend almost 38,000 outpatient appointments.
Speaking at the announcement, Dunajtschik said he had discussed the project with his business and life partner Dorothy.
"Dorothy's prompt answer was, 'I cannot think of anything more worthwhile than doing this'."
Dunajtschik said he was often asked why choose to build a hospital.
"It is no secret, nor commercially sensitive, that a large part of my income is from government departments as my tenants.
"One particularly large department punctually pays their rent every month throughout the year, but they have the curious habit, at the end of the year they ask for one-third back. It is not called a rent refund. It is a three letter word.
"Needless to say, thoughts had crossed my mind - how to stop this money-go-round?
"Suggestions like contacting some creative accountants in Panama were quickly dismissed...the suggestion [of a hospital] appealed to me on the spot."
Dunajtschik joked that he was well into his 80s and during discussions with the DHB they had assured him they were in the health business and would make sure he lived until the hospital was finished.
"I was not sure how to take that comment. But discussed it with Dorothy and her comment was, 'why did you not extend that deal over the warranty period it would have given you another 10 years'."
Coleman said there would be some expense around demolishing existing structures, there could be $7.5m to $12m costs on top that could be met by government.
He said a children's hospital was absolutely necessary.
"This has been raised with over my time as the Health Minister, you talk to parents around Wellington...[the current facility] doesn't have air conditioning, it doesn't have isolation rooms, it is not configured in a way that can deliver modern quality care."
Asked why a private benefactor had to fix that situation, Coleman said there were plans to upgrade facilities "down the track".
Who is Mark Dunajtschik?
Dunajtschik is a major player in property development in Wellington and is behind the five-star convention centre and movie museum project to be built near Te Papa.
He is a long-time benefactor of charitable causes.
His financial help enabled Wellington helicopter pilot the late Peter Button to set up an air rescue service, now called the Life Flight Trust - a service that has been credited with saving 22,000 lives.
