The sea ice surrounding Antarctica shrank to 2.15 million sq km in 2018, the Australian Antarctic Division says.

It follows last year's lowest minimum extent on record of 2.07 million sq km and lowest maximum winter-time sea ice extent of 18.05 million sq km.

The recordings, released on Friday, end a trend of increasing Antarctic sea ice that saw historic highs reached in successive years from 2012 to 2014.

While it's too early to tell whether the continent's shrinking surrounds marks a new trend, AAD chief research scientist Dr Rob Massom says sea ice movements have a "critical" effect on the world's climate and marine biology.

"This annual growth and retreat cycle is one of the greatest seasonal changes on the surface of the earth," Dr Massom says.

Sea ice reflects back between 50 to 85 per cent of incoming sunlight, which forms an insulating blanket on the surface of the ocean that decreases the exchange of heat, moisture and gases between the ocean and atmosphere, he said.

Unlike a watery ocean surface that reflects back seven per cent of sunlight and warms up quickly, sea ice's highly reflective feature is one of many reasons it plays a crucial and pivotal role in the global climate system, the scientist said.

In addition, Dr Massom said sea ice conditions impact shipping and logistical operations in the southern ocean, making forecasting vital.

Despite much scientific progress, the causes and effects of sea ice changes remains a mystery.

"This represents an exciting and indeed high-priority challenge in climate and polar research," Dr Massom said.

"It's an exciting problem to try and unravel."

The researcher has called for more international collaboration on projects, mathematical modelling and state of the art technologies to grasp drivers behind sea ice changes and improve forecasting.

Australian Associated Press