Authorities are calling for urgent help to find an entangled humpback whale thought to be in the Kiama region.
The whale and her calf were first spotted around 600 metres off the coast of Sydney's eastern beaches on the afternoon of Wednesday, August 9.
They were later spotted off Kurnell as they were heading south. By 7am on Thursday, August 10, authorities estimate they will be around the Kiama area.
"When it was spotted it was travelling at normal speed of around six to eight kilometres an hour," ORRCA secretary Jessica Fox said.
Something red coloured is caught on the adult whale, but at this stage ORRCA is not sure what the items are.
"It's not confirmed what's trailing after it, it could be red netting, red ropes or red buoys," Ms Fox said.
Entanglements can be lethal to whales and a National Park and Wildlife Service large whale entanglement team is on standby.
"Depending on where it is entangled it can definitely kill a whale," Ms Fox said. "If the entanglement is around its mouth it can inhibit its ability to feed."
The further south the whales travel the more difficult it will be to spot due to large areas of uninhabited coastline, Ms Fox said.
Humpback whales are the most common variety spotted off the Illawarra.
If you see the whale contact ORRCA urgently on 9415 3333 and provide volunteers with details of where you saw the whale.
Sign up for our newsletter to stay up to date.