A number of neighbours have reported sleep disturbance, health problems and noise issues since the wind farm came into operation in 2008. Both residents and Pacific Hydro have held regular meetings in the past 12 months with mediators.

But Pacific Hydro has agreed to a key request from residents to allow acoustician Steven Cooper to investigate whether noise and power levels correspond with complaints from nearby residents. 

The decision by the company to allow Mr Cooper to measure noise is significant because of Mr Cooper’s previous reports critical of wind farm noise. 

The acoustician has previously stated wind farms are built too close to rural communities and has released studies and submission on the issue — a number of which are carried on anti-wind farm websites. 

Mr Cooper tested inside three homes near the wind farm over eight weeks, including a two-week shutdown of the turbines. 

Preliminary findings in the report say “there is a direct correlation with the external dB(A) level and the power output of the wind farm”. 

The report also found “high sensation levels related to turbines just starting, change in power levels by, say, more than 20 per cent (either up or down) and when wind exceeds maximum power output and blades are being de-powered”. 

A final report is due out in September.

Pacific Hydro is limiting its public comment until the report is finalised.

“We expect to publish the key findings of the final report in September and therefore request that third parties not publicly comment on the findings until that time in light of potential changes that may occur,” the company said in a statement. 

In August last year the company was also forced to issue a public apology after a defective turbine made a screeching noise over several months.