The airport criticised the proposed solar farm last week saying glare from solar panels under the northern landing approach to runway 17 could cause flash blindness for pilots.

Managing director Stephen Byron said the airport had been consulted and had subsequently supported three other solar farms in the territory, but had not been consulted on the Majura development.

Now the airport is widening its criticism, saying the 13-hectare solar plant is proposed on land set aside for the ACT's alignment of a future high speed train.

A consortium which wants to develop the 4MW solar photovoltaic farm under the ACT government's medium-scale solar feed in tariff program rejects the airport's claims.

The land is leased by Majura Winery and stands between the new parkway and Majura Road. It is subject to approval from the federal government's National Capital Authority and the ACT government.

The proponent's spokesman Angus Gemmell says the Civil Aviation Safety Authority does not believe there is a risk to aircraft.

He said the preferred route for any future high speed train was on the other side of Majura Parkway and the site of the development was the least preferred.

The airport has written to the ACT government asking for planning status of the land, and what conditions will change if a power generation station is approved.

Mr Byron said a withdrawal clause in the site's lease could at some point allow for expansion of road works associated with the new Majura Parkway, or a future high speed train.

''Why let someone build a solar farm, a long-term investment with returns over 50 to 100 years, on an area which has a withdrawal clause?

''It is just a contradiction,'' Mr Byron said. He said the proponents only had to move 500 metres to the left or right and they would not be under a flight path.

Mr Byron said the government was building a bridge worth between $8 million to $10 million to access the winery after the construction of the new parkway, presumably for tourism.

''If the (Majura) winery turns (the land) into a solar farm, they won't need the $10 million bridge, will they?''

Mr Gemmell said if the federal government's preferred high speed train route was changed at any stage in the future to the least preferred alignment across the solar farm site, there was enough room to move infrastructure to accommodate it.

''Canberra Airport can be assured the presence of a solar farm is not going to jeopardise any very fast train at any time in the future.''

Mr Gemmell said CASA provided written confirmation to the National Capital Authority that they had looked at reports on solar farms and were satisfied they presented no risk to airport safety.

''I think Canberra Airport have been given a copy of that,'' he said.