Techniquest in Cardiff: Fears for future after budget cut
Science education centre Techniquest is to have its £1.3m grant from the Welsh government cut by 22% from April.
It has also been told it could lose funding altogether by 2019, putting its long-term future in doubt.
The 30-year-old hands-on learning museum in Cardiff and Wrexham relies on the funding for 40% of its income.
Education Minister Huw Lewis said Techniquest was "overly dependent on public funds" and it had to change.
Techniquest said it understands financial restraints and "is prepared to engage with the challenge of moving away from core public funding."
The educational charity is aimed at encouraging young people to engage with science, technology, engineering and maths (Stem subjects).
Since 1986, it has welcomed more than five million visitors, including 1.5m school pupils on organised trips.
It was first set up opposite Cardiff Castle in a gas showroom before moving to Cardiff Bay and it has been in a purpose-built centre since 1995.
It also has a centre on the Glyndwr University campus in Wrexham which was opened by the Queen in 2003.
Last year, 134,273 pupils visited Techniquest.
It also generates around £500,000 a year of its own income and exports interactive exhibits and educational resources to more than 20 countries.
Mr Lewis told AMs earlier that the funding model had to change.
"At a time of budgetary restraint, Techniquest is overly dependent on public funds. It's not a sustainable position, it's got to be restructured," he said.
"I know Techniquest acknowledges that and I've asked officials to work closely with them at a sensible reprofiling what public support for Techniquest looks like."
Techniquest has asked for five years to manage the transition and the Welsh government said it was "working actively with them to explore this and other opportunities in more detail".