Humpback whales have been spotted migrating north up the east coast of New South Wales in what is said to be the highest numbers ever seen this early in the year.

Whale watching season officially runs from June 1 to mid-August but up to 20 whales have already started the journey north for their breeding season.

Rescue groups say that this is likely due to an increasing humpback population but are preparing to be busy after already experiencing two entanglements in a year expected to bring over 35,000 whales along our east coast.