As of 1.30pm Tuesday, more than 240 people had donated almost $22,000.
Page creator Dean Ella wrote: "David is a wonderful person. His friends, family and colleagues love him for being kind-hearted, endlessly thoughtful and funny."
They described him as active and outdoorsy and is a keen cyclist, swimmer, hiker, ultimate frisbee player and an excellent swing dancer.
"It is due to this warm, open, adventurous personality that David has friends from all over the world and all walks of life that are looking for ways to help."
They said there was a lot of uncertainty and one of the ways they hoped to help was by "ensuring that Dave's family do not need to worry about finances. . .whilst they continue to navigate this inconceivable situation."
Police said inquires were still being carried out and the search to date is being reviewed.
Efforts had included a large search last weekend when 148 volunteer searchers helped comb the sand dunes for any items of interest.
None were found.