The comments follow the issuing of a CSIRO report yesterday, revealing drought has cut water availability in northern Tasmania's premier wine growing region by 24 per cent, with riverflows reaching record lows.

One of the report's co-authors, hydrologist David Post, told The Canberra Times there was ''no evidence'' linking drought to climate change in eastern Australia, including the Murray-Darling Basin.

''At this stage, we'd prefer to say we're talking about natural variability. The science is not sufficiently advanced to say it's climate change, one way or the other. The jury is still out on that,'' Dr Post said.

Australian Greens leader, Bob Brown has accused CSIRO of ''caving in to political pressure'' to soften its stance on climate change in the lead-up to this year's federal election.

''We should ask why CSIRO is prepared to turn an unaccountable blind eye to recent climate trends in Tasmania. This undercurrent of scepticism would seem to suggest the report has been politicised,'' Senator Brown said.

According to the report, rainfall in northern Tasmania's Pipers River region famed for its award-winning rieslings and pinot noir has dropped by 12 per cent in the past decade, with recent climate conditions ''drier than those of the last 84 years''.

More than 80 per cent of Tasmania's river catchments have been affected by drought, with the South Esk the island's longest river and source of water for beer production most at risk.