In a letter seeking revised plans for the proposal, council planners said the proposed extension was “inappropriate” and contrary to the provisions of the Kildare County Development Plan on rural design and extension development.
The planners said the proposal was inappropriate “by virtue of its proposed length, scale and massing”.
Architects for the fighter must now go back to the drawing board if they are to progress the plan.
The council has asked the applicant to take account of its views and submit revised plans in accordance with the county’s development plan.
No third party objections have been lodged against the planned extension for the Paddocks home at Castledillon close to the K Club.
The lodging of the planning application followed shortly after McGregor topping the Forbes list of being named the highest paid athlete in the world for 2020/21.
Forbes estimated that in the 12 months to the end of May this year, McGregor earned $180 million (€153 million).
The figure includes $158 million from endorsements and the sale of a majority stake in his whiskey brand.
Planning files at Kildare County Council show McGregor’s partner, Deirdre “Dee” Devlin, gave his personal assistant consent to seek planning permission on their behalf for works on their home in Castledillon.
The MMA fighter acquired the property in a €3 million deal in July 2019 from Albert Reynolds jr, the son of the former taoiseach.
McGregor shows off his new Lamborghini superyacht
The planning application submitted to Kildare County Council on behalf of McGregor and his partner outlines the planned significant alterations and additions to the house’s current configuration.
The proposed works include the demolition of the existing detached garage and the construction of a part-single, part-one-and-a-half-storey extension to the front, side and rear of the property.
McGregor is also seeking to relocate the house’s tennis court and to build a partially sunken basement under it that would contain a car park and gym.
The application will become ‘live’ once more after the revised plans have been lodged.