South Australia is staring down a $2 billion deficit in the current financial year as the state's share of GST revenue is sliced by $1.4 billion because of the coronavirus pandemic.
Treasurer Rob Lucas said Victoria's second shutdown due to the rising number of COVID-19 cases has hit tax revenues.
"If there is less money being spent nationally, the national pool is lower, therefore SA's share is lower," he said.
"Clearly, the impact of their second wave and shutdown is having a significant impact on current and future consumption expenditure."
The national estimates, delivered on Thursday, were based on assumptions that there would be no further lockdowns in other states and Victoria's shutdown would last the anticipated six weeks.
Mr Lucas said the figures suggested state debt would climb to $30 billion by the end of the forward estimates, with the deficit in 2020/21 to be about $2 billion.
"If you don't massively increase taxes or slash expenditure by $2 billion in one year, which would be the worst thing from a jobs and economic recovery viewpoint, the reality will be it will add to the state debt," he said.
Mr Lucas also warned South Australia's unemployment rate could continue to rise and hit 10 per cent by December.
The jobless rate in June came in at 8.8 per cent, compared to the national figure of 7.4 per cent.