Foreign Affairs Minister Murray McCully says Japan has indicated it might be willing to wind down its whaling in the Southern Ocean.
The International Whaling Commission is beginning a crucial five-day meeting in Morocco where countries will be wrestling to end a 24-year deadlock over so-called scientific whaling.
A moratorium has been in force for 24 years, but Japan, Norway and Iceland have caught thousands of whales during that time.
A proposed compromise deal would bring all whaling under the commission's control and set a quota - subject to independent scrutiny - for the number of whales that can be caught in the next 10 years.
Mr McCully says there are some encouraging signs from Japan which has not been taking some of the inflexible positions seen in the past.
Mr McCully says that if the talks fail it could spell the end of the International Whaling Commission. However, the Government won't do any deal the New Zealand public doesn't support, he says.
Environmental groups urge strong stance
Environmental groups are urging the New Zealand Government to take a strong stance at the gathering on conserving whale numbers.
Greenpeace New Zealand says this week's meeting is crucial to breaking the deadlock between pro-whaling and anti-whaling countries and agreeing on a programme which will actually conserve whales.
Forest and Bird is worried the talks could legitimise a global return to commercial whaling.