An expert group drafted almost three years ago to assess the health impacts of wind turbine noise has not yet been able to work out what sounds it should be measuring, despite costing the taxpayer about $500,000.

Key points: Wind turbine committee set up after promise by Tony Abbott

Wind turbine committee set up after promise by Tony Abbott Committee yet to provide advice to Government

Committee yet to provide advice to Government Research papers repeatedly rejected by scientific journals

In a sign the scientists are struggling to establish potential health hazards of wind farms, the committee has not decided to what extent it is necessary to measure low frequency sound or "infrasound" — sound so low it cannot be heard by humans.

The Scientific Committee on Wind Turbines was established more than two years ago, after a promise by former prime minister Tony Abbott who was sympathetic to community concern about wind farms.

The committee was established in December 2015 and given three years to advise government.

With six months to go, it appears the committee is struggling to arrive at some fundamentals.

The committee is required to advise on methodologies in sound measurement and standards for wind farms, cost-effective and continuous sound-monitoring and transparency options for wind farm operators.

"The committee is yet to provide this advice," its annual report says.

"It must first determine exactly what needs to be measured."

The report says it is important to establish "objective methods" to determine whether "special audible characteristics" are present, such as "excessive amplitude modulation" and tonality, noting that these characteristics have "often been determined without the use of measuring equipment".

"This can lead to disputes about the actual presence or absence of special audible characteristics," the annual report says.

Some scientists believe complaints about wind turbines are "psycho-social".

The committee used its seven video conference meetings last year to predominantly discuss research. And it spent four of those sessions talking at length about its 2016 annual report, which is eight pages long.

The most recent annual report reveals the committee's "learned journals" on wind turbine sound were repeatedly rejected by scientific publications.

They included a paper which proposed a potential "sound limit" for Australian wind farms "based on annoyance". That paper was twice rejected by the Journal of the Acoustical Society of America, according to the December 2017 meeting minutes.

The committee then resubmitted its paper to a different journal, which also knocked it back. "The receiving editor of the Journal of Sound and Vibration rejected the paper on the basis that it was outside the scope of the journal," the minutes read.

The committee found no evidence of adverse health effects.

In its 2016 annual report, it said it acknowledged there was a lack of strong statistical research examining the health effects of wind turbine noise.

It agreed with a finding from the National Health and Medical Research Council that there was "inconsistent, poor quality direct evidence of an association between sleep disturbance and wind farm noise".

It went on to concur that there was no "consistent data to suggest wind turbines cause adverse health effects" but acknowledged "such effects cannot be ruled out because of the limitation of current research".

The idea of examining "sound limits" was proposed by national wind farm commissioner Andrew Dyer, whose role was also inspired by Mr Abbott.

Mr Dyer's job is to provide greater oversight and regulation of the industry by helping community members address concerns about wind farms.

Some saw the Coalition's move to establish the scientific committee and a wind farm commissioner as a way to appease Senate crossbenchers who were vocal critics of wind farms.