If Britain leaves Europe in next month's referendum then the first effects could be felt in Australia within weeks, former deputy PM Tim Fischer has warned.
World-wide financial instability would follow in early   July, the former trade minister and ambassador to the Vatican said from Rome, where he has been holding meetings with former contacts. 
"Australia absolutely does not need this at this fragile time," Mr Fischer said.
"Brexit has the capacity to do huge damage and quickly - just as some European economies are showing some signs of much-needed growth, but as Asia struggles with the China downturn."
He said a Brexit would hurt Australia's economy in several ways.
It would reduce trade efficiencies by reinstating protection walls, and "zap confidence" in financial and banking circles. It would torpedo reform of Europe's agricultural policy.And it could also reignite nationalist movements, he said.
"The knock-on could see by 2020 Scotland independent and back in the EU as it desires, Northern Ireland bursting forth again seeking Irish unification and so back in the EU and Great Britain becoming 'Little England' from an own goal before it realises, with the Union Jack torn up and the cross of St Andrew removed," Mr Fischer said.
He said Brexit would be a rejection of the grand alliance that had defeated Germany in two world wars. "France for one will never forgive," he predicted.
Earlier this month Prime Minister Malcolm Turnbull said he would welcome a decision of Britain to stay in Europe, because Australian firms, particularly those based in the UK, benefited from easy access to the EU market.
"It is an unalloyed plus for Britain to remain in the EU, but I stress it is a matter for the British people," he said.
His comments were welcomed by the 'Remain' campaign, but were denounced as "meddling" by Leave proponents.
Exit campaigners have argued Australians would benefit from Brexit, and make it easier for Australians to get visas to study and work in Britain, because there would be less competition from EU citizens.
Brexit spokesman Boris Johnson has argued for a visa-free zone between Britain, Australia and New Zealand.
BREXIT
WHAT
A referendum on whether Britain should remain in the European Union.
WHEN
  June 23, 2016
WHY
Holding a referendum was a 2015 election promise by British Prime Minister David Cameron, in answer to the Eurosceptics, who say the EU no longer served British interests on trade or border control.
WHY IT MATTERS
Leaving could make a spiralling migration crisis worse. The EU is also trying to handle an unpredictable Russia, and facing the prospect of more homegrown terror attacks.
THE CONSEQUENCES
What would it mean for the 3 million EU nationals living and working in Britain under free movement of labour laws? Would Scotland be allowed to stay in, or would that trigger another independence referendum north of the border? Global trade and money markets are already alarmed and US President Barack Obama has urged the UK to stay.
PREDICTION
Polls reflect a nation divided, but with a slight margin for staying.