The state government has withheld from the Commonwealth a survey of rare and threatened plants of an area of the Alpine National Park earmarked for a cattle grazing trial.

It is believed scientists at the state's biodiversity research body - the Arthur Rylah Institute - were asked to look for rare and threatened plants in different parts of the alpine park as part of research for the high country grazing project. Their results were outlined in an unreleased report from May 2012. But the survey was not included in a recent application by Victoria to the federal government for environmental approval of a grazing trial.

Illustration: Matt Golding.

Instead an older desktop study - drawing on previously recorded data - was used to identify the extent of endangered species in the low-lying Wonnangatta Valley, where the latest trial is planned.

The unreleased 2012 plant survey found one nationally protected species of orchid known as pale golden moths and a small patch of endangered alpine bog and wetland in the valley. A large area of rare grassland and a rare plant known as spreading knawel were also found across the trial region.