In a research note, they said the revisions were probably negative for the inflation outlook and negative for monetary policy.
"However, it is difficult to tell exactly how the Reserve Bank will react," Westpac chief economist Dominick Stephens said.
"The best we can say at this point is that the uncertainly around the (Reserve Bank's) June monetary policy statement has increased considerably," he said.
September 2011 quarterly GDP growth is now estimated as 0.2 per cent, rather than 0.7 per cent.
"It is now clear that the recovery has been slow and that economic activity is still around the 2007 level," he said. "The recovery in private consumption and private investment now looks slower," Stephens said.