Mr McCully: "Quite clearly it was an expression of frustration by a lot of people that their economic circumstances haven't improved and there is certainly an anti-immigration tone to the results."
Mr McCully will take a paper to the Cabinet today with a briefing on the possible impacts on New Zealand - besides the US$2 trillion in global wealth destruction in the aftermath of the vote.
He said it could mean a stronger bilateral relationship with Britain, improved visa access for New Zealanders to Britain and a stronger trade relationship in which New Zealand expertise could be helpful.
"It is no secret that we have been lobbying very hard for a better deal for New Zealanders wanting access to the UK," Mr McCully said last night.
"We have found it pretty heavy going.
"We would hope that the next leadership of the Conservative Party and therefore the Government might put a higher value on the relationship with New Zealand."
He suggested that this week the Government will explore the possibility of New Zealand doing an early trade deal with Britain - promoting its own expertise as a benefit to Britain, which has been out of practice given that the EU negotiates trade deals on behalf of members.
"In the trade space there are real opportunities for us, both because we will want to strengthen our bilateral ties but also because we can expect that they will be looking to accomplish in a short time some things that we can probably be helpful with in the trade area.
"It is certainly something we will be talking to our trade people about in the next few days."
The head of the Ministry of Foreign Affairs and Trade, Brook Barrington, will call together a senior officials group this week to co-ordinate a cross-agency response.
The new relationship with Britain could require a boost in resources for the London diplomatic post, he said.
"I suspect we will need to get a broader range of skills involved than would have been the case had it been business as usual."
Current High Commissioner Sir Lockwood Smith is due to return in February next year and Mr McCully said he would turn his mind to a replacement in three or four months.
On the Europe side, however, Mr McCully said Europe would be distracted in having to renegotiate its relationship with Britain and that could cause some delay in the EU-NZ free trade process, which was always going to take some time.