Manx National Heritage insists that any future housing development on its land close to the Grove Museum will not detract from the attraction.
A group of Ramsey campaigners are calling on fellow residents to oppose proposals by MNH to rezone the two outlying fields for housing.
The sites are included among a raft of amendments to the draft Area Plan for the North which were recommended for approval by the planning inspector following a public inquiry last year.
Between them the two sites can accommodate up to 30 homes, 19 in the one off Bowring Road and 11 in the other off Richmond Road.
MNH insists no final decisions have been taken to dispose of both plots but has been considering ‘all options’ for income generation.
It said there are no covenants or other restrictions that would prevent disposal or development of the land but it is currently required to obtain Tynwald approval before any permanent disposal.
A spokesperson for MNH said: ‘The two plots of land are not contiguous with the Grove Museum site as they are separated in each case by an adopted highway and any future housing development on this land will not detract from the Museum or adversely impact a visitor’s experience.
‘The land immediately adjacent to the Grove Museum is not being considered for potential disposal. Any future proposals for developing the sites, should this situation arise, would still require any developer to submit detailed plans with a planning application and the application would then be determined on its merits as part of the normal planning process.’
Manx Museum and National Trust purchased the Grove, its contents and adjoining land extending to 14 acres from the estate of Janet and Alice Gibb for £10,000 in 1976.
Neither the Grove nor the adjacent land was bequeathed or gifted to the Trust.