Prime Minister John Key spoke with Australian Prime Minister Malcolm Turnbull today about how to approach the British exit from the European Union.

"Where it makes sense we will co-operate together," Mr Key said later. "Where it is appropriate we will do things under our own steam."

Mr Key ruled out making any joint approach to Britain to negotiate trade access together but said there could be a chance to "piggy-back each other" in other areas of similarity.

"Where there are similarities, we will probably be able to piggy-back each other."


But there would not be a joint approach for a free trade agreement with Britain because of differences in each's economy.

Mr Turnbull faces a general election on Saturday and took time out of his campaign schedule for the discussion with Mr Key.

Both are former merchant bankers and Mr Key said he expects the global markets to settle down after the "shock and awe" on Friday which saw $2 trillion wiped off the value of global equities after the shock vote.

"Now they have had a chance to digest that and probably get a sense of how long this process ultimately will be, I think the markets will settle down and we will see some of that value restored on the global equity markets," he said at his post-Cabinet press conference.

"Then you will get down to the really hard yards ultimately of both Britain working through its divorce proceedings essentially with the EU; and New Zealand and Australia and the likes having to complete its access arrangements both in the EU and in Britain."

The British would be under pressure because they would be working simultaneously on negotiating their exit from the European Union and the terms of access with non-EU countries such as Australia and New Zealand.

Mr Key did not think it would cause a repeat of the global financial crisis.

The New Zealand economy was stronger than it was in 2008-09 and world markets were more robust.

The long-term implications were more for the British economy and its capacity to compete in Europe than the global stage.

New Zealand's current access arrangements for trade and people to both Britain and Europe will remain in place, in the meantime.

Trade Minister Todd McClay is due to meet his British and EU counterparts at a meeting in China in two weeks.

Both Australia and New Zealand are in the preparatory stages to launch free trade agreements with the EU but doing so separately and at different paces.

Until the vote, the EU was on track to get approval this year from its members, begin talks next year and have them finished by 2019.