The chair of the national museum, Te Papa, says it may fall on private benefactors to ensure many of its exhibitions do not remain locked away in storage.
In its annual briefing to the Government, the museum warns it is close to running out of storage space - and that it will cost about $33 million to expand.
The museum is currently assessing its storage needs as part of a 10-year plan.
Te Papa chairperson Sir Wira Gardiner says they are considering a number of options - including creating more display spaces - either in Wellington or Auckland.
He says the main problem is the lack of funding from the Government - and without substantial donations from New Zealanders there will be little progress.
Sir Wira says the museum is in talks with a substantial benefactor about contributing towards more facilities.