There is a copy of the first bilingual Treaty - a document that was made by missionaries in 1844 to aid understanding between British and Maori but later led to conflict.
The exhibit also includes a silver christening set given by Queen Victoria to her godson Albert Victor Pomare, and Goldie's famous portrait of Ngapuhi chief Tamati Waka Nene.
An 1843 portrait of Queen Victoria has been permanently loaned from the Royal Collection. At three metres tall it was too large to fit in the Treaty House but is now able to be housed in the museum.
Near the entrance to the modern, two-storey museum is a 74kg pounamu boulder gifted by Ngai Tahu after it was found in a West Coast river.
Historian Dame Claudia Orange, who is a consultant to the museum, said it was an important place to tell the stories of Waitangi, both personal and political.
"The exhibition spans the history of Waitangi from before the signing of the Treaty in 1840, right up to the present day," she said.
The Treaty Grounds have partly become known in more recent years for protest and political scuffles, and one of the museum's temporary exhibitions includes photographs of protests.
The museum will open to the public on Sunday.