The pair went missing almost two weeks ago after embarking on a hike of British Columbia in Canada, the ABC reports.
A dive team located the body of Mr Tiffin, 44, in Statlu Lake, British Columbia.
Rescue teams are continuing the search through the rugged and remote terrain for Melbourne woman Ms Dowsley, 34.
"We'll keep searching until either we find her or we have searched everything we can possibly search," Royal Canadian Mounted Police spokesman Corporal Mike Rail told AAP.
"You never give up hope."
The pair’s car was found at the start of the hike, while some of their personal items—including a pair of sunglasses–were discovered at the top of a waterfall.
As Nine News reports, a friend of Mr Tiffin posted an emotional tribute to him on Facebook.
"Today I say goodbye to my long time friend Greg Tiffin, who's been apart of my life since we were 5 years old," they wrote.
"He was funny, sarcastic, meticulous and adventurous.
"It's hard to imagine life without his insight and humor. He will be greatly missed as a beloved son, brother, uncle and as my friend."