"Although there has been some improvement since 1996, as a nation we are not sustainable in environmental concerns," Australian State of the Environment Committee chairman Bruce Thom said yesterday.

The committee reports on the Australian environment once every five years.

While it found the nation's biodiversity was better protected and urban air cleaner, the report highlighted worsening salinity in the Murray-Darling basin which provides 40 percent of Australia's agricultural value.

Thom said 5.7 million hectares (14 million acres) of land were currently at risk from salinity with 17 million hectares (42 million acres) expected to be impacted by 2050.

The report also found the nation's greenhouse gas emissions increased by 16.9 percent between 1990 and 1998.

It said ozone loss over Antarctica appeared to have stabilised during the 1990s, although there was no evidence of long-term ozone recovery.

The Australian government has so far refused to ratify the international Kyoto treaty to cut greenhouse gas emissions. It signed a partnership with Washington last month to find practical approaches to deal with climate change.

Environment Minister David Kemp launched the report yesterday, calling for cooperation between the nation's federal and state governments and local communities to prevent further soil and water damage.

The coalition government has established a A$1.5 billion conservation plan, including A$700 million to battle salinity and water quality.