The Abbott government has agreed to consider new noise restrictions and monitoring of windfarms to win crucial crossbench votes for the inclusion of wood waste in the renewable energy deal now before parliament.

The prime minister, who last week said he found windfarms noisy and “visually awful”, met the Liberal Democratic party senator David Leyonhjelm on Wednesday and discussed noise monitoring and regulation of windfarms.

Last night Leyonhjelm and other crossbench senators concerned about the growth of the wind industry – including the Family First senator, Bob Day, and independent senators John Madigan and Jacqui Lambie – were waiting for a letter from the environment minister, Greg Hunt, setting out the measures the government had agreed to.

The government struck the deal implementing the reduced renewable energy target of 33,000 gigawatt hours with the Labor party and does not need the crossbench votes to get it through the Senate. Leyonhjelm told the Senate on Wednesday he would vote against it.

But at the last minute the government also included the burning of native forest wood waste in the activities eligible under the RET. Labor has said it will try to amend the legislation in the Senate to remove wood waste burning, and the government needs the crossbench votes to defeat this amendment.

Leyonhjelm, Madigan and Day have been using their votes on the amendment to try to leverage concessions from the government to constrain the growth of the wind industry.

The government is understood to have agreed to consider improved monitoring of windfarms and the findings of a new inquiry into noise and health effects.

Despite the RET deal struck by his ministers with Labor this would appear to be an aim with which the prime minister agrees.

Last week in an interview with the Sydney radio announcer Alan Jones Abbott said the RET deal had been aimed at reducing the number of windfarms in Australia.

“What we did recently in the Senate was to reduce, Alan, capital R-E-D-U-C-E, the number of these things that we are going to get in the future … I frankly would have likely to have reduced the number a lot more but we got the best deal we could out of the Senate and if we hadn’t had a deal, Alan, we would have been stuck with even more of these things …

“What we are managing to do through this admittedly imperfect deal with the Senate is to reduce the growth rate of this particular sector as much as the current Senate would allow us to do.”

Madigan has proposed noise monitoring amendments to the RET legislation aimed at “protecting the community from excessive noise and sleep deprivation” but it seemed unlikely these would pass.

Coalition senators are also hoping that their new federal inquiry will call for commonwealth oversight of windfarm regulations and demand recognition of the alleged health impacts of turbines on people living near them – and it is these recommendations the government has promised to consider. The crossbenchers are also involved in the inquiry (Madigan is its chair).

In a report released in February, the National Health and Medical Research Council concluded that “there is currently no consistent evidence that windfarms cause adverse health effects in humans”.

The council is also responsible for implementing the Coalition’s election pledge and is offering grants worth $500,000 for five years for more research on windfarms and human health.

A Sydney University review of 25 studies into the possible health effects of wind turbines found none had produced evidence they were detrimental to human health and in 2014 the Australian Medical Association issued a statement saying the available evidence did not support the idea that windfarm noise harmed humans.

After the election, Abbott took responsibility for the renewable energy target review himself and appointed the businessman and self-professed climate sceptic Dick Warburton to head it.

The head of his business advisory council, Maurice Newman, another climate sceptic and campaigner against windfarms, had already been urging him to scrap the RET altogether.

Initially he argued the review was needed because the RET was forcing up power prices, but then modelling, including some commissioned by the review itself, found this was not true.

The policy divided the cabinet, with leaks revealing Abbott favouring the idea of closing the RET to any new investment and Hunt and the industry minister, Ian Macfarlane, fighting for it to be “pared back” rather than closed – although Abbott never said this publicly. He sent initial drafts back, asking the review to do more work on ways to close the scheme to new entrants.

In the end the review provided two recommendations, allowing the government to either close or pare back the target.

But a huge public backlash, enormous voter support for renewable energy and steadfast opposition from Labor, the Greens and crossbench senators overwhelmed the government’s intentions – forcing it into negotiations with Labor, which resulted in a deal to cut the target from 41,000 gigawatt hours of renewable energy by 2020 to 33,000 gigawatt hours.