Plans are being drawn up to turn Bretton Hall into a luxury hotel.
Developer Rushbond wants to create a 120-bed hotel at the site, in a scheme the company says would create hundreds of jobs.
Planning permission was granted last February for the proposal, which would see former Leeds University buildings at the site become a hotel and business park.
Now Rushbond has said a first phase of the plan will see the hall restored to become a 40-bed hotel with restaurant and conferencing and banqueting facilities. New office space would also be created under the first phase.
Mark Finch, director of Bretton Investment Partnership, which is part of Rushbond, said: “The hall is a magnificent listed building which sits within a very sensitive site of international significance.
“We have been developing a detailed phasing plan through a patient and considered approach with the dedicated input and support of English Heritage and Wakefield Council. It is our intention to submit these plans for formal approval very shortly.”
Coun Denise Jeffery, deputy leader of Wakefield Council said the project could boost tourism and investment and help create jobs around the district.
She said: “The redevelopment is a highly significant and important project not only for Bretton and the Yorkshire Sculpture Park but also for the district as a whole.”
Wakefield Council bought Bretton Hall from the University of Leeds after it was closed as a campus in 2007.