It remains to be seen whether the United States will pull out of the Trans Pacific Partnership (TPP), Prime Minister Bill English says.
US President-elect Donald Trump has vowed to scrap the trade deal on his first day in office.
But Mr English, who is in London, told the BBC that New Zealand would continue to promote it.
He said many of the signatories to the deal regarded the US as the prize, but for this country Japan represented another large economy that was keen to participate.
Yesterday Japanese Prime Minister Shinzo Abe and Australian Prime Minister Malcolm Turnbull also reaffirmed their support for the trade deal.
In his first visit to Australia since Mr Turnbull became Prime Minister, Mr Abe said both leaders were committed to ensuring the 12-country TPP trade deal would come into effect.
"On the economic front we agreed that we should demonstrate anew the importance of free trade," he said.