SNP depute leader Keith Brown said the country could close the gap between what it earns and what it spends without having to resort to austerity by greatly reducing spending on reserved matters like defence.
His comments followed the publication this week of the 2019 GERS report that found Scotland's deficit, although down from 8.5 per cent the previous year, is now six times higher than the rest of the UK.
The Tories countered that reducing the deficit at the speed proposed by Mr Brown would lead to steep tax rises and schools, hospitals and infrastructure cuts to the tune of £7.2 billion.
Labour leader Richard Leonard claimed that such a deficit reduction plan would lead to "shock austerity" and even deeper cuts than those implemented by former chancellor George Osborne.
But the SNP MSP insisted the latest GERS figures proved the performance of Scotland's economy was "robust" and its future growth was threatened by a potential no-deal Brexit, not independence.
“Following the Growth Commission model, Scotland's starting deficit would be reduced by a further 1.5 per cent by reducing spending on reserved matters such as defence and debt," Brown wrote in a column in The National.
"This year, the deficit fell by one per cent. So, on that trajectory, it would only take us less than three years from now to get to the Growth Commission target of three per cent - something which was predicted to happen gradually, over the course of 10 years."
Scottish Labour leader Richard Leonard claimed it was "now clear" that the SNP's plan for independence would mean the budget for public services being slashed.
“The SNP’s plan to leave the UK is based on a prospectus of shock austerity on Scotland twinned with ditching the pound for a separate currency," he said.
“All of Scotland’s public services, including our NHS, would be in the SNP’s firing line to meet such draconian fiscal targets. The people of Scotland now have a clear choice between austerity and cuts with the SNP and the Tories, or £70 billion worth of new investment with a Labour government."
Scottish Conservative MSP Donald Cameron said: “These claims could be laughed off were it not for the fact they’ve been made by the deputy leader of Scotland’s governing party.
“Presumably this means it’s now SNP policy to seek ongoing tax hikes worth more than £7 billion, or cutting public services by an equivalent amount.
“Put simply, that means devastating cuts to schools, hospitals, councils and infrastructure - at the same time as hiking personal taxes for millions of ordinary working Scots. Neither is an acceptable option, which is why the nationalists must take the threat of another independence referendum off the table.
“No-one thought the SNP could get more fanciful and deluded than its infamous and derided White Paper. But Keith Brown is now doing exactly that.”