The incident reportedly happened early Tuesday morning, local time, at Pescadores beach in the coastal town of Ericeira, a popular surfing spot about 30 kilometres from Lisbon.
The Department of Foreign Affairs and Trade told news.com.au it was providing consular assistance to the family of an Australian who died in Portugal.
Rui Pereira da Terra, head of the rescue service in Cascais port, near Lisbon, said it appeared the pair was taking a selfie when the tragedy happened.
"Everything seems to indicate that the fall happened when they were probably trying to take a selfie," he told AFP.
"It seems they dropped their mobile phone and fell down while leaning over to retrieve it."
The Portuguese Lusa News Agency reported the couple was a woman aged in her 30s and a man in his 40s.
They were found dead on the beach by a worker cleaning the beach. It is believed the incident happened between 1am and 6am on Tuesday.
The Australian Embassy in Lisbon was notified about the death, the agency reported.
Friends have taken to social media to pay tribute to the couple.
Liz Catchpole wrote on Facebook: "No words can describe what we have lost. Louise Benson you had a passion for life. Your smiles infectious, your laughs amazing, your friendship invaluable and just the love you have out.
"In shock and speechless. You will be missed and I will miss you so much. Love you Lou, one in a million. Lou&Mike 4ever."
Tina Dorant wrote: "My fellow ocean warrior. You are an amazing person and will be missed. I can't believe it still and my heart goes out to your family and friends. RIP Louise Benson. Condolences to your family. I'm shocked and saddened."
This is not the first time tourists have fallen from the wall near the beach, known as Praia dos Pescadores or Fishermans Beach, AFP reported.
