11-time world champion Kelly Slater was spotted surfing around Sydney on the weekend as massive waves slammed into the NSW coast.

Late last week, a low pressure system rapidly deepened close to the NSW coast as a pool of cold upper-level air moved over the Tasman Sea. As the system grew more intense, it created storm force winds that generated a large and powerful southerly swell.

By Friday night, maximum wave heights were exceeding 13 metres off the coast of Port Kembla and 11 metres near Sydney.

The low remained intense and slow-moving as it lingered over the Tasman Sea through the weekend. This allowed a powerful and persistent southerly swell to pummel the NSW coast.

Image: Visible satellite image showing cloud around the Tasman Low on Sunday.

Maximum wave heights near Sydney exceeded 11 metres again on Sunday, topping out at 11.6 metres in the early evening.

The result of the long-lasting and powerful swell was a display of huge waves that most could only stand by and watch. But for Sydney's most skilled and bravest boardriders, it was a chance to share the water with a world champion.

Image: Kelly Slater surfing at a break called Deadmans, near Manly Beach on Sunday. Source: @craigbrokensha / Instagram

Kelly Slater was seen surfing at Avalon Beach on Friday, where he reportedly broke his board, and at a break called Deadmans near Manly Beach on Sunday.

Image: Bronte on Saturday. Source: @welsh_phill / Instagram

Wind and swell will gradually ease along the NSW coast in the coming days as the Tasman Low weakens and eventually moves towards New Zealand.