The projected cost of the upgrade was an early, ballpark figure, and the focus on any initial rebuild would be on the main ward block, he said.
"To do all we want to do would cost a lot more than that and as we know when it comes time to fund construction, building costs are likely to have gone up."
Mr Snee said that the DHB had, through its own financial management, spent about $60 million over the past five to six years on capital upgrades.
"Raising that kind of money is doable, on top of other ongoing infrastructure investments, but we will need to find substantial money for the work on the ward block and other areas that are a bit decrepit or not very well designed."
This would mean an approach to Government and he said there had been a lot of thinking about how to work within the existing footprint of the hospital.
He said the first steps would be to let the Ministry of Health know the situation and the DHB's long-term plans.
"When we get closer we will talk about money - the system is aware of it and knows that it's not 20 years away, it's sooner."
The future capability and capacity of the hospital was currently under review through the clinical services plan, a report on which was due at the end of April next year.