MORE than a decade after the Howard government hailed the clean-up of Maralinga as completed, the government is continuing to support remediation at the former British nuclear weapons test site.

Confidential files released under freedom-of-information laws show Canberra officials have at times been mainly concerned with ''perceptions'' of radioactive contamination while rejecting a request by the Maralinga Tjarutja Aboriginal community for a site near the Maralinga village to be cleared of high levels of contamination. Files released by the Department of Resources, Energy and Tourism show erosion of the massive Taranaki burial trench north of Maralinga, described by officials as ''a large radioactive waste repository'', has required significant remediation. Other burial pits have been subject to subsidence and erosion, exposing asbestos-contaminated debris.

While the documents indicate ''no radiological contamination of groundwater'' has been detected, the government has been obliged, under its 2009 agreement with Maralinga Tjarutja for the handback of the test site, to initiate further work.

The Taranaki trench was used to bury radioactive debris and soil, mainly from numerous ''minor trials'' - British nuclear weapons safety and development experiments - that between 1956 and 1963 caused the heaviest radioactive contamination.

A brief prepared in April for the Minister for Resources and Energy, Martin Ferguson, questioned the capacity of the Maralinga Tjarutja to manage the site.