"It's part of the ice shelf's normal cycle, where we see major calving events every 60-to-70 years."

The last major iceberg to break off the Amery shelf, located between Australia's Davis and Mawson research stations, was in late 1963 or early 1964.

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Scientists expected the latest calving to be at a different spot.

"We knew it would happen eventually, but just to keep us all on our toes, it is not exactly where we expected it to be," Prof Fricker said.

The new iceberg won't impact sea levels, as it was already floating.

"Much like an ice cube in a glass of water," Australian Antarctic Division Glaciologist Dr Ben Galton-Fenzi explained.

"What will be interesting to see is how the loss of this ice will influence the ocean melting under the remaining ice shelf and the speed at which the ice flows off the continent."