Scottish Labour said the economic arguments for leaving the UK are “in tatters” while the Conservatives accused the SNP of deception on oil figures during the 2014 referendum.
Forecasts for revenues have been downgraded by the UK’s fiscal watchdog.
The Office for Budget Responsibility (OBR) projects offshore receipts of about £4.6 billion between 2017/18 and 2021/22, down from £7.3 billion in its November forecast.
It estimates revenues of £0.9 billion in 2017/18.
The Scottish Government had predicted North Sea oil revenues of up to £7.9 billion in 2016/17 and of up to £11.8 billion in 2017/18 prior to the independence referendum.
Last week, Andrew Wilson, chairman of the SNP’s growth commission, suggested oil revenues would not be central to the economic case for independence in the future.
Scottish Labour’s economy spokeswoman Jackie Baillie said: “The SNP’s economic case for independence now lies in tatters.
“The official projections for oil and gas revenues have been revised downwards yet again.
“Scottish Labour warned time and again during the independence referendum campaign about the SNP’s rose-tinted fantasy of an independent Scotland’s finances.”
Scottish Conservative finance spokesman Murdo Fraser said: “These are troubling figures which only serve to reinforce the current fragility of Scotland’s oil and gas sector - and shows why the support announced by the UK Government today is so necessary.
“It also throws the SNP’s deception on oil prior to the independence referendum into stark relief.”