They said deer were damaging a range of parks including the Dandenong Ranges National Park, as well as the Kinglake, Yarra Ranges, Alpine and Grampians parks.

Invasive Species Council chief executive Andrew Cox hit out over the lack of information on the size of the deer population and the damage it caused.

"The trends show that there is a growing population of feral deer in Victoria. It doesn't show the full size. We know from anecdotal reports that the range is expanding," he said.

"The fact that we don't actually have a handle on the numbers in Victoria is, I think, an indictment on government policy on feral deer. We don't have a clear estimate of the extent and the damage they're causing. We know that they're causing lots of damage."

Mr Cox said deer were competing with native animals for feed and were "opening up rainforest gullies; they're feeding on ferns and they're rubbing against rare plants".

"[They're] pushing out species like wombats and lyrebirds and competing with them."

Phil Ingamells​ from the Victorian National Parks Association said wild deer were "a very big problem" and their population was increasing and covering a wider area.

"So for all sorts of reasons, it just has to be dealt with," he said.

The comments came after The Age revealed on Thursday that licensed deer shooters killed a huge number of deer in 2013-14, a record 57,945.

The estimate is contained in a new Game Management Authority report. The report has no information on the size of Victoria's wild deer population, but that licensed hunters have killed more than 265,000 over the last six years suggests the population is large and widespread.

Meanwhile, a program operating in the Dandenong Ranges National Park and two other parks near Melbourne's eastern edge, in which hunters work with Parks Victoria to shoot deer, has been applauded.

Ecologist Alex Maisey, convener of the Sherbrooke Lyrebird Survey Group, called for the program to be expanded to other parks, like the Yarra Ranges National Park.

"It's important for all parks with deer problems, to extend this control program," he said.

Mr Maisey documented damage in the Sherbrooke Forest section of the park via remote cameras, which recorded scores of deer, from young to mature. They images were taken in 2013.

However, since the culling program began in 2014, the condition of the forest had improved.

"It's been a terrific success. In terms of numbers, it seems like only a few animals, but already I've seen a huge improvement in the habitat. There are still deer there, but they're not as settled in one area, so the impact is spread out over a greater area," he said.

Parks Victoria figures show 100 deer were killed last year in the Dandenong Ranges National Park, Warramate Hills and Yellingbo nature conservation reserves.

District manager Craig Bray said Parks Victoria had secured a new permit to continue the program this year.

It allows for up to 220 deer to be killed.

"We've seen a reduction in the number of wallows, we're seeing green pick come back, where it previously had been browsed, grazed and trampled by deer in some areas. So we are seeing an improvement in the habitat, that's what the intent of the program is," he said.

Parks Victoria said the deer control program would continue while deer were "still having a negative impact on sensitive vegetation in the three parks".