Te Papa's chairperson fully supports the idea of exhibiting more of the national museum's art in a new building but says money could be an obstacle.
The museum in Wellington has been heavily criticised in the past for displaying only a tiny percentage of its 15,000 artworks at any one time.
Board member Chris Parkin has proposed the idea of a separate art gallery owned by Te Papa, which could cost $100 million.
Te Papa chairperson Sir Wira Gardiner told Checkpoint he likes the concept, but needs to discuss it with the board.
"The Government hasn't got any money, we haven't got any money, the city council hasn't got any money.
"If it does get off the ground, it needs to be essentially a private benefactor or benefactors who like the idea and are prepared to put money into it."
Sir Wira says Te Papa is about to set its vision for the next 10 years and hopes the gallery proposal can be included.
Prime Minister John Key says the idea for a separate gallery has been canvassed for some time and is possible, but the Government is unlikely to fully fund it.
Mr Key says the Government has been approached by two philanthropists interested in helping to build the art gallery.