"If they vote 'out' on Friday morning our time, you will have the financial markets doing cartwheels immediately afterwards. I think it is in the interests not only of Britain but in the interests of a more stable world that they vote to stay in."
NZ First leader Winston Peters has argued that Britain leaving the EU (a "Brexit") would be an opportunity to reverse immigration restrictions on New Zealanders, given migration from Eastern Europe would probably decline.
Mr Bolger, Prime Minister from 1990 to 1997, didn't agree.
"The arguments to me are not based on economics, they are based centrally on xenophobia. And therefore I cannot see any pluses coming out of that for New Zealand."
The Leave arguments appealed to those with a "deep distrust, if not worse" for Brussels, Mr Bolger said.
"Most of that is based on the belief that we don't want people telling us what we should do. This is coming from a country that as an empire told most of the world what to do."
Former Labour Prime Minister Sir Geoffrey Palmer said, whatever the result, deep divisions in British society would remain.
During a visit to England in February, Sir Geoffrey said his strong impression was that working-class people were in favour of an exit, because of concerns about immigrants' effect on the job market and essential services.
Business people and those he spoke to at universities were strongly in favour of remaining in the EU.
"I think the split is pretty much right down the middle in British society, and I think it's going to have pretty profound ramifications, whatever happens. This is a rather parlous situation for the British and I feel sorry for them. Because I don't think, whatever happens, it's going to be permanently resolved on Thursday."
Sir Geoffrey said he could understand voters' frustration that many decisions were in the hands of politicians in Brussels who weren't directly accountable.
"I think I would probably vote to remain, but I wouldn't be very confident about it. You've either got to have something like a federation where there is a central European Government and various independent states with legislatures, or you've got to go back to where it's essentially a trading arrangement.
"But at the moment it's sort of poised unevenly between those two things."
Sir Don McKinnon, the former Commonwealth Secretary-General who lived in Britain for 10 years, favoured Britain staying in the EU.
He said one British employer who worked across Europe had told his staff that if Britain left the EU he would have to make half of his workforce redundant.
"So I have a feeling there is real angst amongst the commercial community this could be lost on emotion, and really the wrong emotion."
The Brexit referendum
What: Britain is voting on "Should the United Kingdom remain a member of the European Union or leave the European Union?"
When: Polls open 6pm today and close 9am tomorrow (NZ times). Results come through from 3pm tomorrow.
The polls: Leave and Remain are neck and neck according to the Telegraph's average of the past six polls. Ladbrokes have odds of 1/4 for remaining in the EU and 3/1 for leaving.
What then? If a majority vote to leave the EU, British Prime Minister David Cameron will immediately trigger the formal process to leave the EU. Negotiations will take at least two years.
Stay or go?
Leave
NZ First leader
Winston Peters
This is a decision for the people of the UK alone to make.
It's not for leaders of other nations to tell them what is in their best interests. However, should they decide to leave the UK's economy will not be laid waste as the fear merchants so falsely and shrilly claim.
Departure from the EU presents the UK with the chance to restore real economic ties with the Commonwealth. In 2014 the Commonwealth produced GDP of $10.45 trillion, a massive 17 per cent of gross world product. In recent years, Commonwealth GDP growth has been 5 per cent compared to the Eurozone's 0.7 per cent.
London has been a global financial centre for centuries. In the EU or out, that will not change. Departure from Europe, therefore, would not be an ending but the beginning of a new era in which the Commonwealth could become an economic colossus.
Remain
Green Party co-leader
James Shaw
It is up to the British people to decide their own fate. But we do think that the EU is generally a force for good in the world, and our preference would be for Britain to remain. With our main export markets in Asia, Brexit is unlikely to be a disaster for New Zealand. But rather than look at this through the lens of our own narrow self-interest, we should ask what's best for the world.
The EU isn't perfect, but it has been a strong force for action on climate change and human rights. And the post-War vision of a united, cosmopolitan Europe is as relevant today as it ever was.
