By Agence France-Presse
The world's top male and female surfers had been taking part in the 12-day Margaret River Pro, which is part of the World Surf League Championship Tour, off Australia's southwest coast since April 11.
The contest was briefly suspended on Monday morning after a local surfer suffered leg injuries in a shark attack off nearby Gracetown, some 260 kilometres (160 miles) south of the Western Australia state capital Perth.
A second surfer, reportedly from Denmark, suffered a gash to his leg in a second shark encounter, also near Gracetown.
"Today, the WSL has made the difficult decision to cancel the remainder of the Margaret River Pro, as a result of exceptional circumstances surrounding this season's event regarding sharks and the safety of our surfers," WSL chief Sophie Goldschmidt said in a statement.
"The WSL puts the highest premium on safety. This cannot be just talk, and it cannot be compromised."
They said while sharks were an "occasional reality" of WSL competitions, the current circumstances were "very unusual and troubling".
The tour's co-leader, Brazilian Italo Ferriera, took to Instagram on Tuesday to express his fears about being in the water, writing in Portuguese that he did not feel comfortable training and competing near the attack sites.
Fellow countryman Gabriel Medina, the 2014 WSL world champion, wrote on Instagram that he too did not feel safe competing in the area.
Authorities had also issued an alert over a whale carcass off an area beach, concerned the decomposing creature could attract sharks. The carcass was removed from the area Tuesday.
The cancellation came three years after Australian surfing great Mick Fanning, who retired from the sport earlier this month, made global headlines when he fought off a shark on live TV while competing in the WSL's J-Bay Open in Jeffreys Bay, South Africa.
Fanning was not injured and that competition was cancelled after the encounter.
Experts say shark attacks are increasing as water sports become more popular and bait fish move closer to shore, but fatalities remain rare.