The poll, on the CCTV.com, CYOL.com, Tom.com and IFAW.org websites from June 2 to 6, received 2,893 votes, with 91 percent saying "China should resolutely oppose Japanese whaling", five percent approving of whaling, and four percent unconcerned.
"Whales are part of the natural environment and we cannot leave only pieces of whales for future generations," a voter nicknamed Ni Ya wrote on CCTV.com. "China should vote against Japan to protect the whales."
Japan has been lobbying some countries to vote for commercial whaling, which IWC has banned since 1986, at the meeting to be held in the Caribbean island state of St. Kitts and Nevis from June 16 to 20.
"Given the current situation, it would not be an exaggeration to say that China's vote may play an important role in stepping upthe anti-whaling campaign," said Jeff He, an official with the International Fund for Animal Welfare China office.
A Chinese government official, who declined to be named, told Xinhua that it would be improper for the government to publicize its stance before the vote, but China had no whaling culture and strictly abided by the IWC ban on commercial whaling.
Two countries supporting Japan -- the Marshall Islands and Cambodia -- joined the IWC ahead of its decision-making plenary session, Japan's Kyodo news agency reported on Monday.
As the admissions had brought the number of IWC members to 69, Japan's most optimistic projections put the number of countries supporting its bid at 36, with 32 against and the stance of one unknown.
Japan was confident that the pro-whaling camp was about to secure a majority, Kyodo said.
If this happens at this year's meeting, Japan aims to propose scrapping the Conservation Committee, officials of Japan's Fisheries Agency have said.
In 1986, the IWC implemented a global moratorium on whale hunting. Japan continues to hunt whales arguing that the IWC permits whaling for scientific research. It classifies its whaling operations as "scientific" despite acknowledging that the meat and blubber from its catch are processed and sold commercially in Japan. Experts say Japan is misinterpreting the rules.
"It would be a tragedy if commercial whaling were to be approved this year," said Yu Jie, the government and public affairs officer with Greenpeace China.
"You can marvel at a whale again and again, but you can only kill it once," Yu quoted an observer as saying