In the Liberals' first public comments on the proposed Williamsdale solar farm since its announcement in March, Nicole Lawder said concerns for trees and cockatoos led her to oppose Elementus Energy's claim for an exemption from preparing an environment impact statement.

"The fact that they're considering exempting them from lodging an EIS rings some alarm bells for me," she said.

"It's an environmental pursuit, which is a good thing, so why are you trying to dodge an EIS?"

Meeting with five or six residents on a visit to the area with Liberal colleague Brendan Smyth on June 30, Ms Lawder said there was concern for the yellow box trees – part of the 203 which would be demolished under the solar farm plans – and a colony of glossy black cockatoos in the area which she was investigating.

"It would appear to me that the locals' views that [the solar site] should be moved seems quite reasonable and I would support that, but I'm working on the evidence base to support that," she said.

Neighbours' claims of unrecorded builders' waste dumps from eight to 10 years ago, about 500 metres west of the solar site on the same block, were another reason for Planning Minister Mick Gentleman to refuse the exemption, she said.

"The timing sounds right from when the tip fees were introduced and builders started looking for alternatives – at that time the inclusion of bonded asbestos does seem quite likely, so that is a major concern and needs to be fully investigated."

Assessments prepared for the exemption application said there would not be an adverse impact on the existing disturbed farmland, and the sensitivity of impacted fauna to the works was minor given their "capacity to move to nearby less disturbed habitat". The solar farm would be built on the same site as the shelved 20-megawatt array proposed by ActewAGL, which had a similar exemption application approved in 2012.

Mr Gentleman said the exemption application was under assessment by the planning and land authority, taking into consideration issues raised during the public consultation which ended on June 2. Issues, including any possible contamination, would be addressed at the later development application stage, he said.

Neighbours Brett and Michael McDonald said an agent of developer Elementus told them they knew there was an asbestos dump on the solar farm block. There was no comment this week from consultant Rob Purdon, who has met with the brothers this year.

Elementus Energy managing director Ashleigh Antflick has said the company had no knowledge of asbestos dumps on the site.