The effect of climate change on the ecology of krill and whales in the Southern Ocean urgently needs monitoring, a group of Australian scientists warn.

The Australian Antarctic Division scientists say the effects of climate change on the sea ice that breeds krill which feeds whales can no longer be ignored.

"It is a matter of urgency that long-term studies are initiated to examine variability and change at all trophic levels in the Southern Ocean ecosystem to reduce uncertainty and to improve predictive power," Stephen Nicol, Anthony Worby and Rebecca Leaper say in their paper published on Thursday in the journal Marine and Freshwater Research.

Dr Worby on Thursday told AAP that, basically, less sea ice means less krill and less krill could also mean fewer whales.

The massive declines in Arctic sea ice has not been repeated in Antarctica but the Antarctic Peninsula is one of the most rapidly warming areas on the globe, he said.

"The concern is that if we have a significant decline in the amount of sea ice around Antarctica what does that mean for the krill habitat and what does that mean for whale populations," he said.

The study was particularly concerned with the ecological effects of climate change on baleen whales and the reproduction of krill, the Southern Ocean staple which feeds and breeds under the sea ice.

Sea ice is projected to shrink in the Arctic and Antarctic under all future emissions scenarios, the study says.

If the sea ice environment changes and if this is associated with changes in oceanic circulation, then it will undoubtedly affect the ecosystems on which predators such as baleen whales depend, the study says.

There is now unequivocal evidence of long-term changes in the physical environment of the Antarctic region that are thought to have a dominant effect on biological productivity in the sea ice zone, it says.

"Understanding the changes occurring in Southern Ocean ecosystems will require concerted integrated studies in the future, and not a little ingenuity," it says.