ENVIRONMENTALLY significant parts of the Dandenong Ranges National Park have been degraded by Parks Victoria, an environment group claims.

Knox Environment Society spokesman Richard Faragher said there had been significant clearing by Parks Victoria along forest tracks and the park's boundary.

He said the "destruction" had occurred along Chandlers Hill Track in The Basin, as well as near Olivebank Road and Perra Street in Ferntree Gully.

"The Chandlers Hill area has a population of state-significant acacia leprosa, which is a beautiful weeping wattle."

Mr Faragher said mature trees had been removed and soil and drainage in the area had been disturbed.

"It has also seen the removal of many plants in an area well known for some beautiful wildflower displays and the mature trees that many animal and bird species rely on for nesting."

Mr Faragher said the problem began in 2008, when Parks Victoria conducted a "poorly planned and managed control burn" that killed mature eucalypts and led to the loss of eastern grey kangaroos and echidnas.

"Once we lose a precious resource like this we can't get it back and perhaps only then will we realise what we have lost."

Parks Victoria fire operations officer Anthony Nimbs rejected the claims. He said it was a delicate balancing act to manage appropriate fire preparedness while maintaining the important environmental values of the park.

"The clearing referred to is part of recent work to upgrade the existing fuel break network. This work has improved the access for firefighting vehicles and increased the buffer to nearby homes. To date, 27kilometres of fuel breaks have been upgraded."

Mr Nimbs said fire preparedness works were carried out each year in accordance with a fire preparations plan, which was open for public comment every August.

"Records of threatened flora and fauna species as well as any cultural values are checked as part of planning for any burn or major works in the park. If significant vegetation communities are recorded they are replaced in another location to ensure there is no overall reduction."

He said it was extremely unlikely that eastern grey kangaroos had been lost due to planned burns and that there were no records of acacia leprosa in the Chandlers Hill area.