She said the day would see the hosting of an array of events from billy tea to a Mad Hatter's tea party.
"We're encouraging kids to make a crazy hat and we'll have a Mad Hatter's tea party where the Mad Hatter will judge who has the best hat."
Ms McKenzie said the museum has come a long way since it first opened its doors.
"It started as one building and it's got bigger and bigger over the years.
"We have the Pioneer Hall, the Gumdiggers Hall, we have a Maori Hall, a music room - lots, it depends what you're interested in," she said.
-Access to the museum is usually $15 for adults but, on Sunday, will be free. The event will run from 10am-4pm at Harding Park, Dargaville.