Prof Jon Waters, of the zoology department, was commenting on new research which shows the Antarctic is not as isolated from the rest of the world as scientists had previously thought.
``The results suggest that Antarctica won't be immune from drifting plastics that are increasingly a problem in the world's marine ecosystems,'' Prof Waters said.
``It also highlights the potential for new species to colonise Antarctica as the climate warms.''
The research, reported today in Nature Climate Change, was undertaken by an international team, including Prof Waters.
The scientists used DNA analysis to show that kelp had drifted 20,000km to reach the Antarctic-making it the longest known biological rafting event ever recorded.
``It's quite a surprise.
``It's quite astonishing that something has moved that far.
``I think it's a game-changer. We used to think the Antarctic was going to be safe,'' Prof Waters said in an interview.
The findings were also an ``absolute wake-up call'' about the dangers posed by drifting plastic, which could prove a ``disaster'', and where kelp could be driven by storms, plastic could also follow.
The research was led by Dr Ceridwen Fraser of the Australian National University, who has an Otago zoology PhD supervised by Prof Waters.
DNA samples taken from the kelp revealed it had drifted from the Kerguelen Islands in the southern Indian Ocean, and had to pass through barriers created by polar winds and currents that were, until now, thought to be impenetrable.
Another specimen was from South Georgia, in the South Atlantic.
The findings highlighted the importance of intense storms, in moving material closer to the Antarctic, and there were also important implications for the science of ocean drift that was used to track plastics, aeroplane crash debris and other floating material across our seas.
The study builds on a previous Marsden-funded project led by Prof Waters, with Dr Fraser.
Dr Fraser said the finding showed living plants and animals could reach the Antarctic across the ocean on kelp rafts, and temperate and sub-Antarctic marine species were probably bombarding Antarctic coastlines all the time.