Shadow chancellor Ed Balls welcomed the economy's emergence from recession but said the Government needs to do more to "secure and strengthen" growth.
"It's good news that, with the help of the Olympics, Britain is finally out of the longest double-dip recession since the Second World War," he said.
"Our economy desperately needs an injection of confidence. But this is no time for complacency and wishful thinking.
"Today's figures show that underlying growth remains weak and that our economy is only just back to the same size as a year ago - 12 months of damaging flatlining which has seen borrowing rise in the first half of this year.
"And with living standards falling, more tax rises on the way, small business lending down and the eurozone still in crisis, it would be very unwise of David Cameron and George Osborne to just sit back, cross their fingers and hope for the best.
"The complacent thing to do now is simply to wait and hope things will get better. The cautious thing to do is to act now to secure and strengthen growth in our economy."
He compared 0.6 per cent growth overall since the 2010 spending review with 3.4 per cent in the US and 3.3 per cent in Germany.
"The question for the coming months is whether and how we can catch up all the ground we have lost over the last two years and not keep falling behind as other countries move ahead."