Japan and New Zealand should boost business relations not only in trade of agricultural products but in the areas of environment, technology, forestry and education, visiting New Zealand Prime Minister Helen Clark said Friday.

Clark proposed the idea in talks with Prime Minister Yoshiro Mori at the Prime Minister's Official Residence, saying details should be discussed at the next round of bilateral talks to be held by the end of this year in Japan, a Foreign Ministry official said.

Mori supported Clark's idea, the official said.

However, the two leaders differed over the issue of whaling, with Clark indirectly criticizing Japan's whaling program and Mori reiterating that it was for scientific research. Clark was quoted as saying New Zealand supports making the South Pacific a whaling sanctuary.

In turn, Mori said Japan wants to discuss the matter scientifically and calmly. "If the (whale) resources are rich, they should be utilized effectively," the official quoted Mori as saying.

Clark also urged Japan to join in an international treaty that sets quotas for catching tuna in the western and central Pacific, which Japan has not signed. Japan claims that the treaty is unfavorable to fishing countries.

Mori asked Clark to consider Japan's stance at the next preparatory meeting for realizing the treaty, which will be held in September in New Zealand, the official said.

Clark, who is in Japan for six days, is due to leave Monday evening for Hong Kong.