The owners of the Australia Walkabout Wildlife Park, which was founded by the former federal environment minister Barry Cohen, have written to the Department of Planning to oppose the mine, at Calga, on the Central Coast.

The mine, being considered by the Planning Department, would also be close to the venue for the annual Peats Ridge Music Festival.

Rocla Quarry Products operates a sand mine next to the proposed site, but wants to increase the sand it mines from 400,000 tonnes a year to 1 million tonnes.

Tassin Barnard, who runs the wildlife park with her husband, Gerald, said they already experienced noise and dust from the current mine, which is about two kilometres away, and if the extension of the mine went ahead it would be ''unbearable''.

Resident groups agree and argue that if the mine goes ahead it could pose health risks to people and animals, and endanger important Aboriginal rock carvings, including a rare women's site.

Ms Barnard said she had been told by the Department of Industry and Investment that the park could be forced to shut because of the noise and dust.

Silica dust, produced by sand mining, is a known carcinogen that can lead to fatal diseases such as silicosis and lung cancer.

Last year then planning minister, Kristina Keneally, refused an application for a sand mine at Somersby Fields, on the Central Coast, because of its potential ''social and environmental consequences''. Residents argued that silica dust from the mine could affect Somersby Primary School, which was about 200 metres from the proposed site.

However, Rocla's Central Coast regional manager, John Gardiner, said the residents' claims about the risk caused by the silica dust were about a ''perceived'' danger rather than a real one. ''In my opinion it is part of the hysteria they are trying to generate,'' Mr Gardiner said.

A 2006 article by Shabir Banday, of the London School of Hygiene and Tropical Medicine, found that most studies into the effects of silica examined workplace, rather than environmental, exposure to the dust.

Mr Gardiner said Rocla had committed to preserving the rock carvings on the site.