The works were scheduled to begin on Monday despite concerns they could interrupt the breeding season of wedge-tailed eagles that inhabit the area.

A Justice Department spokesperson said the works were delayed after they received information from the federal government about how the Environmental Protection and Biodiversity Conservation Act could apply to the proposed drilling.

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Westbury Region Against the Prison president Linda Poulton said the group turned up to the proposed site on Birralee Road, north of Westbury, on Monday, to protest the drilling, but found no activity.

She said the group was concerned the breeding season of eagles that inhabit the area would be affected by the works.

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"The government is saying it is outside the 500-metre management zone, which is not the appropriate measure for this type of activity, nor is the line of sight," Ms Poulton said.

"The appropriate measure is whether there is likely to be a disturbance of breeding eagles there. That is the only question that needs to be asked and noise generation is certainly one of those things that can drive breeding eagles off a nest."

The other concern the group had was whether the government has received the required approvals to undertake works on the Birralee Road site.

"As we understand it Parks and Wildlife would have to undertake a reserve activity assessment before any activity like that went on there," Ms Poulton said.

"We understand they did issue such a permit for the works to go ahead there - so we would like to see a copy of that and make sure it has been appropriately issued."

A department spokesperson said the Parks and Wildlife service had provided a written works authority to allow the works to go ahead.

The spokesperson said no work would be undertaken within the 500-metres no disturbance zone in place for the eagle breeding season.

"Whether the nest is currently being used will be confirmed by a survey to be carried out later this month. The timing of this survey is consistent with eagle nest activity checks undertaken by the forestry industry," the spokesperson said.

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