A NSW Department of Primary Industries surveillance crew were treated to a very rare sight this afternoon.
At about noon today the crew flew over south Sawtell and spotted a mother and calf sei whale.
The pair of whales were travelling north.
The sei whale is one of the fastest species of whale, reaching speeds of almost 100km/h according to the World Wildlife Foundation.
Sei whales are endangered but can be found in all oceans and adjoining seas except polar and tropical regions.
They spend the summer feeding in cooler waters and migrate to warmer waters to breed.
Sei whales range from 45 to 66 foot long.