Photo/IllutrationA minke whale is caught during research whaling off the coast of Hachinohe, Aomori Prefecture, in May. (Asahi Shimbun file photo)

The central government will postpone announcing the maximum number of whales that can be killed for commercial purposes out of concerns of a backlash at the upcoming Group of 20 meeting in Osaka.

Commercial whaling is set to resume in July for the first time in 31 years.

The figure will be announced after the completion of the June 28-29 meetings, which will be attended by anti-whaling countries, including Australia, and chaired by Prime Minister Shinzo Abe.

It will be the first time for Japan to host the G-20 summit.

Japan decided in December last year to withdraw from the International Whaling Commission (IWC), which is led by countries opposed to whaling.

After the official withdrawal on June 30, Japan will halt whaling in the Antarctic Sea and North Pacific Ocean for the purpose of research and focus on commercial whaling within its exclusive economic zone.

It will be Japan's first commercial whale hunt since 1988, when it halted such activities in response to the IWC's moratorium on the practice.

Referring to the number of whales that can be taken under commercial whaling regulations, fisheries minister Takamori Yoshikawa said: "It will be within a range determined by a calculation method adopted by the IWC. Under such a calculation, the whale population will not have decreased even after 100 years of whaling."

Hunting vessels are scheduled to set off from Shimonoseki, Yamaguchi Prefecture, and Kushiro, Hokkaido, once commercial whaling begins.

"We want them to release (the range) as soon as possible, as we need to make preparations," said an official of the Japan Whaling Association.

The fisheries ministry has already determined the maximum figure and conveyed it to the prime minister's office, according to a source.

"We'll announce the cap for the number of whales (that can be hunted) after the G-20 summit is complete," a government official said.

Another government official told reporters that the figure could be announced July 1 when commercial whaling resumes.