He says the Government is genuinely and desperately committed to getting the thing resolved and it is talking to the insurers to try to get them to do the same.
Mr Key says it may be slow, but it is progress and they are still gaining ground.
He says in places such as New Orleans, years later, there is no sign of any progress at all.
Mr Key says the CTV building hasn't been an easy issue, as families continue to fight for justice.
Family members of the 115 people killed when the building collapsed during the February earthquake have expressed their disgust at the lack of accountability.
A police investigation is still ongoing five years later.
Mr Key says he understands the pain and suffering of the families.
He says there are some real questions about the integrity of that building. "It hasn't been an easy issue. It's been subject obviously to reviews and the likes and we'll continue to work our way through it as best we can."