Sunday's pro-whaling declaration, won by a majority of 33 votes to 32, calls for a move towards lifting the 1986 ban on commercial whaling.
The IWC statement said whales were responsible for depleting fish stocks and described environmental groups as a "threat".
However, the approval of the non-binding declaration by the IWC does not immediately threaten the end of the whaling ban - which would require a 75% majority.
"This is historic. For the first time in more than two decades the Whaling Commission expresses support for commercial whaling," said Rune Frovik, secretary of Norwegian pro-whaling lobby the High North Alliance.
Anti-whaling groups expressed their dismay at the outcome of the vote.
"This is a huge disaster," said Kitty Block of Humane Society International shortly after the vote. "This is now going to be their propaganda."
Japan has abided by the moratorium on commercial whaling since it came into force two decades ago, but, along with Iceland, uses a legal loophole to conduct scientific whaling.
Norway is the only country that ignores the ban.
More than 25,000 whales have been hunted and killed since the moratorium.