Funding cuts could affect the next stage of the renovation of a former colliery in Stoke-on-Trent.
The Chatterley Whitfield site has reopened as a country park with the next stage of the work focusing on renovating some of the old buildings.
English Heritage, which is helping with the £8m scheme, said its financial commitment remains.
But it added this will have to be assessed when it knows the effects of the Spending Review.
"English Heritage is committed to working with Stoke City Council, and its partners, to find an appropriate solution to the buildings within the scheduled area at Chatterley Whitfield," a statement said.
It is hoped the old buildings will be transformed into business units.