The United Kingdom's decision to vote to leave the European Union was motivated by emotion and panic, Australian business leaders say.

On Friday Britain voted to leave the EU, wiping tens of billions off sharemarkets and creating angst and uncertainty about the longer-term impact the decision will have on the global economy.

The ASX posted its worst day since August last year, with the S&P/ASX 200 ending 3.2 per cent lower at 5113, muted in comparison to Japan's Nikkei which sunk almost 8 per cent.

But it wasn't economic decisions that, in the end, swayed the outcome of Britain's historic vote to leave the EU.

Kerry Stokes - Seven Group

The executive chairman Seven Group holdings, said people in the United Kingdom had voted to protect their borders, following the recent influx of migrants into the EU.

"The Brits have decided to do what Australians have already decided to do, which is to protect our borders," Mr Stokes told Fairfax Media.

"The major concern was being able to protect their borders. They voted for that over their economic concerns."

Mr Stokes did not think there would be much impact on trade with Australia.

"Sensible people will negotiate sensible outcomes," he said. "And there is two years to negotiate a trade exit for Great Britain. I would expect by the time they finish [negotiating] a trade agreement will be favourable for both parties and life will go on." 

Gerry Harvey - Harvey Norman

The Harvey Norman founder said he was surprised by the move, and confused why the United Kingdom even went to a vote on the matter in the first place.

"People voted emotionally," he told Fairfax Media, " ... probably because they were incapable of voting on anything else. I think that about 95 per cent of those that voted had no real comprehension about what it means. It defies all logic why they would have a referendum on something like that."

He said there was an element of people voting based on fear. "Look people listened to [British PM] David Cameron say one thing and [former mayor of London] Boris Johnson say another. There may have been some fear about protecting borders but it was uninformed."

Mr Harvey said he did not expect the impact on Australia would be significant. "I think the world's quick to panic," he said.

Mike Cannon-Brookes - Atlassian

Atlassian co-founder expressed his surprise over the leave decision on social media, shortly after the results were known. "Britain. Wow. What did you do?!" he tweeted. 

Shayne Elliott - ANZ

ANZ's chief executive said the decision was "certainly a surprise and while it was always tipped to be close, I think most in markets globally expected a vote in favour of remaining."

He said it would be too early to predict the long-term economic impact, but so far the decision had "caused significant volatility and dislocation in markets that will impact funding costs in at least the short term".

"We've been preparing for both scenarios for many months and we're reasonably well positioned to wait for stability to return," he said.

Richard Goyder - Wesfarmers

Wesfarmers' chief executive spoke to ABC's RN Breakfast shortly before the vote saying that there were strong reasons for Britain to remain.

He stuck by Bunnings' decision to acquire the Homebase British hardware and garden chain in January, saying it would have happened regardless of the outcome. "We are confident that over the long run this will be a good investment," he said.

Britain's pound sterling suffered its worst day of trade ever, plummeting from $US1.50 to a 30-year low of $US1.35. The Australian dollar fell from above US76¢ to US73.5¢, while the Japanese yen surged to a three-year high and gold prices soared as much as 7 per cent to about $US1345 an ounce.

Nader Naeimi - AMP Capital

As head of dynamic asset allocation at AMP Capital, said it was a "nasty day" for the markets. "The market wasn't prepared for [Brexit], that's why we're getting the shock,' he said. 

Paul Taylor - Fidelity International

The head of Australian equities at Fidelity International, said the vote had thrown up a whole set of new questions around the potential exit from other members of the EU or unrest within the United Kingdom itself. Scotland and Northern Ireland both voted in favour of remaining within the EU.

"It's going to be an overhang on things for a while," Mr Taylor said.

With Elizabeth Knight, Brian Robins