Patrick Harvie, co-leader of pro-independence Greens, has hit out at Nicola Sturgeon's economic case for leaving the UK in the week of the fifth anniversary of the 2014 referendum.
But SNP Deputy leader Keith Brown insisted that the party's plans will allow the Scots economy to grow and free up investment for public services.
The last five years have made a second independence referendum inevitable, Mr Harvie said, but he says the next vote should be held on a more radical prospectus.
“In 2014 the SNP got caught in the trap laid by Better Together which saw them make a continuity case for independence," Mr Harvie said.
“It became about retaining the monarchy, membership of NATO, the pound and various other trappings of the UK’s discredited system. This meant things like currency became a major factor in the result.
“Unfortunately, the SNP’s response to that has to become even more conservative. The much-heralded Growth Commission suggests tight spending controls, extended use of the UK’s currency and continued austerity. It would create a little Britain, not a new Scotland."
Thursday marks the fifth anniversary of the 2014 vote. Nicola Sturgeon has set out plans for a second Scottish independence referendum next year and legislation is being passed at Holyrood which would pave the way for this to take place. But it has so far been vetoed by the UK Government which has control over the constitution.
Mr Harvie added: “Scotland has suffered enough under austerity and a system which puts economic growth above basic living standards. Poverty and inequality are rising, and we need to use reserved economic levers to tackle the climate emergency.
“If the SNP want to win independence it should get behind our Scottish Green New Deal, which is all about building a fairer, more sustainable Scotland by abandoning the failed economic orthodoxy and becoming a forward-looking European nation.”
But Mr Brown defended the approach of the party's Sustainable Growth Commission which set out plans to cut the country's deficit by restricting rises to the rate of economic growth.
"Independence will give Scotland the ability to set economic policy in our own interests, instead of being tied to an increasingly arrogant and dangerous Tory government," he said.
"The Tory austerity model has failed Scotland. Our economic plan, as set out by the Sustainable Growth Commission, shows how an independent Scotland could use the powers of independence to grow our economy and invest in our public services.
"Indeed, the latest GERS figures show that Scotland's public finances are already stronger than the Growth Commission's assumptions. The opportunities of independence stand in stark contrast to the economic damage posed by Brexit - replacing uncertainty and fear with optimism and hope about Scotland’s future."