Members of Newport City Council's (NCC) cabinet have agreed to press ahead with plans to transfer the management of the historic Tredegar House to the National Trust (NT).
Negotiations are continuing between NCC and NT with a view to finalising an deal that will see the council retain ownership of the property and the trust take on a long-term lease.
According to a recent survey, around £4.5m worth of work would be required to ensure that Tredegar House was maintained to a good condition, along with other buildings on the site.
By transferring its management to the NT, it is hoped that visitor numbers will increase and that the future of Tredegar House and its gardens would be safeguarded.
It comes as the Vale of Glamorgan Council put forward plans to transfer the operation of Dyffryn House and Gardens in St Nicholas to the NT.