A total of 735 whales have been counted off Cape Solander between the beginning of the whale watching season on May 24 and Sunday, June 11.
And between May 24 and June 4, volunteers at Cape Solander in Kamay Botany Bay National Park had spotted 302 humpbacks.
The whale count is being compiled at Cape Solander by whale watching volunteers Wayne Reynolds and Chris Rasborsek.
An estimated 30,000 humpbacks are expected to pass the NSW coast this year on their annual migration from the Antarctic to warmer breeding grounds north.
The NSW Office of Environment and Heritage estimates that the number of humpback sightings is increasing by 10 per cent each year.
Last year, 3032 whales were counted at Cape Solander during the official whale watching season which went from May 24 to July 31.
This was the highest number of humpbacks ever recorded at Cape Solander.
Overall, up to 24,000 humpbacks passed the NSW coast in 2016.