The Baird government will cut $20 million from environment agencies this year in an "efficiency" drive, with National Parks and Wildlife and the Royal Botanic Gardens among the hardest hit.

The latest efficiency cuts come on top of $60 million already stripped from the environment department over the past three years.

"Rangers are not as visible": walkers on the Coast Track in the Royal National Park. Credit:NSW NPWS

Australia's largest bush walking group, the National Parks Association, said the impact can be seen in national parks, where rangers have become scarce.

"Rangers are not as visible because they are spread too thin. They are more likely to be behind the desk or cleaning toilets," said the association's chief executive, Kevin Evans.