Adult visitors will now be charged $15 to see Sir Peter Jackson's The Great War exhibition in Wellington's Pukeahu National War Memorial Park.
The exhibition is the second most popular attraction in the capital after Te Papa, according to Travel website TripAdvisor, but it was set up with minimal ongoing operational funding. The pressure to deliver day to day, as well as develop the exhibition, is proving costly.
Fran Wilde, chairwoman of the National Military Heritage Charitable Trust, which runs the exhibition, said the business model that was adopted when the exhibition opened 10 months ago was not financially sustainable.
"Visitor numbers have been very high - well over 180,000 since opening in April 2015. But running the exhibition is resource intensive, with our guided tours proving very popular.
This success is putting pressure on slim resources, with high need for crowd management, security and cleaning services, as well as the customer service staff.
"In addition, we are planning other improvements and new features for the exhibition over the next two years. Some but not all of the latter will be funded by charitable grants we have received. In particular, we hope that in the middle of this year we can open our exciting Trench Experience, providing a realistic, immersive sensory experience. We anticipate that this will be a major attraction."
The Great War Exhibition, designed by Sir Peter, profiles the history of the four years of World War I from the perspective of a number of different countries, while highlighting the special role of New Zealanders. It considers the impact of all forces -- navy, army and air force.
Ms Wilde said the trust had begun an "active programme" to attract more sponsorship and invited businesses interested in supporting the exhibition to get in touch.
"Although we know some will be disappointed at the introduction of an entry charge, it will help support the viability of the exhibition and ensure we can continue to offer a positive visitor experience, while maintaining a firm base for future development."
The adult charge of $15 will be introduced from Tuesday. There will be no charge for visitors aged 16 years and under. Any adult buying a ticket will be eligible to return for a free visit within 12 months if accompanied by one paying visitor. The price for school tour groups remain the same -- $2 a child.
Guided tours remain at $10 an adult and $5 for a child, but the child age has been raised from 11 to 16 years.
Capital funding was provided initially through the Ministry for Culture and Heritage and the Wellington City Council, with ANZ the principal partner. Future development is being supported through help from the Lottery Grants Board and Pub Charity.