Export New Zealand's cautious but reassured by the Prime Minister's promises that there will be no immediate change to trade with Britain.

The country voted to split from the European Union, leaving it up in the air as to whether trade deals made under the EU would remain until Britain's exit was negotiated.

Those negotiations could take up to two years.

Executive director Catherine Beard said if the New Zealand government's had assurances that it will be business as usual during that time, then that's positive for exporters.

"That certainly gives the industries affected time to maybe try to diversify or make other plans if they think they're not going to get good access."

Kiwi exporters are good at switching and developing new markets, and trends point to all of our food going to Asia, she said.

International law firm K&L Gates said its lawyers are working overtime following the Brexit vote, with the firm's putting number of measures in place to deal with the fallout.

Managing partner Nick Nichola said one of those is a 24-hour-hotline for companies to call if they've got concerns.

"That's the biggest issue for our clients.and corporations globally. It's a state of flux, a state of uncertainty. I think a lot of people would not have expected this result."

K&L Gates works with multinational and middle-market companies, as well as entities in the public sector.