The proponents of a $670 million wind farm west of Yass have not consulted properly with 23 airstrips in the area, or provided enough information to AirServices on impacts on radar equipment near the wind farm and near Canberra Airport.

In a scathing assessment which has thrown into doubt the project's future, NSW Planning and Environment found aircraft from nine of the rural airstrips may not have achieved enough altitude before reaching the wind turbines.

An independent review cited in the assessment found that impacts at these airstrips needed to be fully understood, particularly in relation to aircraft performance and departure gradients, which would determine whether or not an aircraft would be able to obtain sufficient obstacle clearance and turn safely.

Neighbouring farmers who waged a long campaign against the project have cracked open champagne to celebrate the department's findings, while a spokesman for proponent Epuron Projects, Andrew Wilson, says he is surprised.