Australia ordered an urgent review Monday into the consequences of Britain leaving the EU and said it would team up with New Zealand to negotiate new trade and immigration deals.

The trans-Tasman neighbours have been rattled by the British public's decision to leave the European bloc, with Australian Prime Minister Malcolm Turnbull calling it "a very big shift".

He ordered a review from the Treasury, the Reserve Bank and financial regulators, in consultation with London and Brussels, on the implications of Britain's exit, to be delivered next week.

Turnbull said dealing with the fallout alongside Wellington made sense and after talks with New Zealand counterpart John Key had agreed to work towards a "collaborative, cooperative framework".

"We have a lot of common interests with our neighbours in New Zealand and the New Zealand Prime Minister John Key and I have discussed the implications of Brexit today and they are considerable," said Turnbull.

"We have many, many common interests in terms of dealing with that, both from a trade point of view, from a movement of persons point of view.

"There are some big issues in terms of the access of Australians and New Zealanders to Europe and, indeed, to the United Kingdom, a whole lot of issues to work on."

Australia goes to the polls on Saturday and Turnbull said that if returned to office he would meet with Key soon after to chart the way forward and "ensure that we maximise any opportunities that arise out of these changes".

Canberra and Wellington are both separately negotiating free-trade deals with the EU and once Britain leaves will also have to do the same with London.

Australian trade with the EU in 2013-14 stood at Aus$83.4 billion (US$61.6 billion) while the United Kingdom was the seventh-largest by country at Aus$20.3 billion, according to official statistics.

In New Zealand, trade with the EU, including Britain, was NZ$19.6 billion ($13.9 billion) in 2014-15, making it the country's third largest trading partner, official data showed.

Key said he did not expect Brexit to have a major impact on New Zealand's trading arrangements with either Britain or the EU.

"In terms of New Zealand's access for people and goods, I'm quite confident that position is OK because of the assurances I've received," he told Radio New Zealand.