New Zealand's Foreign Affairs Minister Murray McCully says other countries may look to use the ruling on Japan's Antarctic whaling programme as a precedent for similar action in the north Pacific.
On Monday, the court at The Hague ruled that Japan's killing, taking and treating of whales in the Antarctic is not for the purposes of scientific research and it must stop all whaling with immediate effect.
The case was taken by Australia and supported by New Zealand. Japan says it will abide by the ruling, but will not say when it will stop hunting whales.
The ruling concerns only whaling in the Southern Ocean. However, Murray McCully said the same arguments could be mounted against Japan's programme in the north Pacific, where fishermen carry out small-scale coastal whaling.
McCully said the ruling is greater than he had hoped for - but it may not necessarily be the end of whaling, as Japan may now try to devise a new programme. "Our task is to carry out a diplomatic conversation that dissuades them from embarking on that course."
The minister said he believed it would be difficult for Japan to adjust its current programme to get around the ruling, and should now be given time to consider the decision. ''Japan has always been a strong follower of international law and rules."
Mr McCully said New Zealand representatives would meet with their Japanese counterparts in coming weeks to discuss the rulings and Japan's intentions.
The Labour Party said Japan places a lot of importance on international order and the rule of law, and welcomes the early signals it will abide by the decision. However, it said diplomatic efforts are now needed to ensure that new loopholes are not found to circumvent the ruling.
The Green Party says it hoped Japan will respect the International Court of Justice decision. MP Gareth Hughes is encouraging the nation to cease its Antarctic programme altogether and in the north Pacific.
"This has been a very clear ruling by a majority of the judges. We've got a good relationship with Japan, they're a county which, in many respects, sees the importance of international laws and norms."
Australian Attorney-General George Brandis welcomed the court's decision, but said he wants to review it more closely.
Australia's representative at the court and former Attorney-General, Mark Dreyfus, said there is a range of non-lethal scientific research methods that Japan could use. He cited the example of scientists from the Antarctic division operating out of Hobart who have recently developed satellite tracking devices for whales.
Court's ruling final
Japan has used the 1946 International Convention for the Regulation of Whaling, which permits killing for research, to justify killing whales in the Antarctic.
But judges at the International Court of Justice agreed with Australia that the Japanese research - two peer-reviewed papers since 2005 based on results obtained from just nine killed whales - was not proportionate to the number of animals killed.
"In light of the fact the Jarpa II (research programme) has been going on since 2005, and has involved the killing of about 3600 minke whales, the scientific output to date appears limited," presiding judge Peter Tomka of Slovakia said.
"Japan shall revoke any existent authorisation, permit or licence granted in relation to Jarpa II and refrain from granting any further permits in pursuance to the programme."
Japan signed a 1986 moratorium on whaling, but has continued to hunt up to 850 minke whales in the icy waters of the Southern Ocean each year claiming it is for scientific research.
The ICJ's ruling is final and there will be no appeal. It is the first time any country had used an international court to try to stop whaling.
Japan 'disappointed, but will comply'
In a statement, Japan said on Tuesday it was deeply disappointed with the ruling, but would comply with the decision.
While it has committed to abide by the ICJ ruling, Japan would be free to continue whaling if it revises its scientific programme, or withdraws from the International Whaling Commission.
Japan had argued it has complied with the moratorium despite its 2000-year tradition of whale hunting, leaving coastal communities in "anguish" because they can no longer practise their ancestral traditions.
Nori Shikata, a spokesperson for Japan's delegation in The Hague, told Radio New Zealand's Morning Report programme on Tuesday the country needs to examine the judgement before committing to a timeframe for ending the programme.
Sea Shepherd to continue campaigns
Australia's legal victory over the Japanese does not mean the end of anti-whaling organisation Sea Shepherd's campaigns.
Representatives were at the court to hear Monday's ruling. Global executive officer Alex Cornelissen said the decision ruled almost on every count in favour of Australia.
Mr Cornelissen later told Morning Report it was a 12-4 decision and a clear statement that the international community is fed up with Japan's whaling programme.
He said there is still a lot of whaling going on throughout the world which Sea Shepherd will continue to challenge. "We'll refocus our attention either to the northern whaling of Japan or perhaps the Atlantic Ocean where both Iceland and Norway still conduct whaling."
A vessel from the Sea Shepherd anti-whaling organisation, the Bob Barker, is docked in Wellington after ending its latest campaign in the Antarctic.
Boatswain Phil Peterson said the court's decision came as a surprise. ''I couldn't believe what I was hearing, I didn't think the decision was going to go that way. Justice has been served.''