The 120-page report has been prepared for Defence by G-tek Pty Ltd, a specialist unexploded ordnance (UXO) contractor and member of the Defence Environment and Heritage Panel.

A defence spokesperson said the 2013 report on Tianjara contained sensitive material, was not written for public distribution and was not available to the public.

“The report contains personal details of interviewees and provides legal opinion that would be subject to privilege,” the spokesperson said. 

“There is also information that has been taken from restricted Defence files.”

The area is now part of the Morton National Park, with Defence saying the fact it was used for military training and had a residual UXO issue was well known. 

“At various times since the 1960s, the known areas of UXO contamination have been published on maps used by bushwalkers,” the spokesperson said.

“The National Parks and Wildlife Service (NPWS) have promulgated that information on their website and signage around the park.

“It also uses the information to assist in its bushfire management planning.”

Defence said most of the area was a national park and was managed by the NPWS, which was responsible for the management, planning and use of the area.

“Defence will continue to provide advice and assistance to the NPWS to aid in their management of the UXO issue but has no control over any future plans for the area,” the spokesperson said.

The Register understands a number of Sassafras landowners, whose properties are adjacent to the range’s northern boundary, have been notified as a consequence of the report that their land had been categorised as being slightly contaminated.

Documents on the Defence website said the area was used for manoeuvres and live fire practices from early World War II until 1974, with most army weapons systems fired on the range, including 18 and 25 pounder, 105mm, 5.5 inch, and 40 millimetre artillery and 4.2 inch, three-inch and two-inch mortars, as well as aircraft air to ground ordnance.

The website states the area has a history of numerous UXO finds or heavy residual fragmentation and in areas where categorisation had been applied, assessments of residual UXO potential referred to substantial or slight levels.