Police said a woman's body was found at a Potts Point unit on Sunday afternoon after concerns were raised for her welfare.

She's yet to be formally identified and there are no apparent suspicious circumstances, a police spokeswoman told AAP.

The Sydney-based model, actress and designer was known for her roles on shows including Fat Pizza, Home and Away and 20 to 1.

Australian actor and fellow Fat Pizza star Rob Shehadie took to Twitter on Monday to pay tribute.

"So sad and gutted to hear about the passing of Annalise Braakensiek, she was an amazing person. I will always cherish the great memories we had on the set of Fat Pizza and on tour. God rest your soul Annalise," he tweeted.

Celebrity agent Max Markson, interior designer and stylist Alex Zabotto-Bentley, and actress Michala Banas also took to social media to express condolences.

Braakensiek, 46, worked closely with a number of charities, including as an ambassador for suicide prevention charity R U OK?.

In November, she took to Instagram to speak about her own mental health struggles.

"Mental health has so so many misconceptions, criticism, misunderstandings and false judgments still!! We have to break the silence on mental health because it happens to the best of us," Braakensiek posted alongside an R U OK? image.

"Thank you from the bottom of my heart to all of you who have helped me through my dark clouds.... now I'm strong enough to help my loved ones who unfortunately are not in the best place right now. But we will get through this!"

A statement released by R U OK? said the organisation was "devastated to hear of the loss of much loved and respected" Braakensiek.

"We are still processing the news we have heard today. Annalise has been a huge voice for suicide prevention in Australia," chief executive Brendan Maher said in the statement.

"Nothing we have ever asked of Annalise was too much, she has stepped up time and time again to share our message, even when she was going through her own tough times."

Braakensiek also worked closely with the Starlight Foundation, Cancer Council and Olivia Newton-John Cancer Centre.

A post-mortem examination will be held to determine the cause of death.

Lifeline 13 11 14

beyondblue 1300 22 4636

Australian Associated Press