An Eirgrid architect has insisted that the proposed North-South interconnectors "will not have a significant impact" on views from the important site at the Hill of Tara.
But a consultant for Meath County Council claimed there would be a high impact on a view of national significance.
The differences emerged at a Bord Pleanála oral hearing in Carrickmacross into one of the biggest ever pieces of infrastructure in the State.
Joerg Schulze, consultant landscape architect for EirGrid, said that, from the hill, the transmission line to the east would not dominate the landscape. It would be located in the middle distance, with the closest pylon being 6.29km away, and would not be immediately apparent.
The Hill of Tara, with its Iron Age hilltop enclosure, is Ireland's ancient capital. It is a candidate Unesco world heritage site.
EirGrid said that, in identifying a potential route for the interconnector, it took into account key constraints such as architectural and archaeological heritage sites.
Meath County Council engaged Conor Skehan of planning and environmental consultants CAAS Ltd to assess all designated scenic viewpoints that were included in the County Development Plan. He concluded that seven views including Tara and at Bective Bridge would be affected by the proposed development.
Mr Schulze acknowledged that while he agreed with most of the assessments made by Mr Skehan, there was a considerable difference of opinion with Meath County Council regarding the effect on Tara.
He showed the photomontages to the planning inspectors along with a picture that superimposed the line of the pylons. Mr Schulze pointed out that an existing 220kV line from Gorman to Maynooth that was only 1.25km away was not immediately apparent and was barely discernible.
The proposed 400kV development would be located approximately 4.5 to 5km further away from this 220kV line, according to EirGrid.
The hearing resumed at the Nuremore Hotel at 11am yesterday with a module on 'Human Beings: Land Use'.