More than 120 pregnant whales were slaughtered in the latest Japanese whale hunt in Antarctica’s Southern Ocean, new documents show, reigniting calls for Australia to step up efforts to stop the annual killing spree.

A further 114 immature whales were killed as part of the so-called “scientific” whaling program, according to meeting papers from the International Whaling Commission’s scientific committee meeting this month.

A minke whale is unloaded in Kushiro, a port on Japan's northern island of Hokkaido, in 2013. Credit:AP

Japan insists on conducting its annual summer whale hunt – including killing in Australian whale sanctuaries - despite international condemnation.

The latest figures show that of 333 minke Antarctic whales killed last summer, 181 were females. Some 122 females, or 67 per cent, were pregnant.