Internal Affairs Minister Peter Dunne is backing the decision to move the Treaty of Waitangi documents, despite the project costing $3 million so far.
The Government announced plans in 2012 to move the treaty documents from their current home at Archives New Zealand to the National Library in Wellington, 200 metres down the road.
The new display was meant to open in 2013, but the project had to be revised and it's now scheduled to open in 2017.
Mr Dunne has defended how much it has cost so far.
"They're not in the best state at the moment. I think it's important that we make sure that these things, our core heritage, are available and accessible," he told reporters on Tuesday.
"It's not just some documents, it's the Treaty of Waitangi, it's the 1835 declaration, it's some documents that are critical to the history of New Zealand."
Mr Dunne said it's "unfortunate" the project has taken so long.