Commuters in Sydney were treated to a rare sight on Tuesday morning as a Southern Right Whale and its calf were spotted swimming together near the city's harbour.

The two whales were swimming close to the shore, which does not usually happen.

The total global population of the species is estimated to be around 10,000.

Onlookers went to great lengths to get a closer look, with some even getting into kayaks to move nearer to the mammals.

Wildlife rangers said the two whales were likely to remain in the area for a short while.

Southern Right Whales spend the summer close to Antarctica, before moving north in winter for breeding.