Duncan Craw, 32, travelled from Warrnambool with his wife Taylia and young son Levi for a camping trip in South Australia earlier this week and was snorkelling at Surfers Way near Port MacDonnell in South Australia when Tay lost sight of him in the water on Thursday.

A shredded wetsuit led police to believe Mr Craw was the victim of a shark attack, just three days before his 33^rd birthday.

"It's impossible to adequately describe our grief and shock," the family said in a statement.

"We wish this was all a bad dream. It's also impossible to fully explain the hole this will leave behind in the lives of all the relatives and friends who love Duncan."

Mr Craw was a hard-working and dedicated operations manager at an agriculture contracting company in Warrnambool where he grew up after relocating from New Zealand at a young age, the statement said.

When he wasn't farming, spending time with his family, or working around the property he bought with Taylia, he liked catching up with friends and watching or playing sport, including with Woolsthorpe Cricket Club.

He was also the best father to Levi and a beautiful husband and best friend to Taylia, his high-school sweetheart.

"He was a cheerful, loving, helpful son. He was a kind and cheeky brother to his sisters. He was a fun-loving, mischievous and supportive mate who had a heart of gold," the statement said.

"We will never forget Duncan and we will make sure his memory lives on.

"Duncan loved snorkelling and accepted the dangers he may face in the ocean. He was extremely unlucky this time.

"On behalf of all Duncan's family across Victoria and in New Zealand, we thank all the search and rescue crews and all the selfless volunteers for their tireless efforts and for the care shown by everyone who has offered their help during this awful time."

Police operations manager for South Australia Limestone Coast Inspector Campbell Hill said emergency services were contacted just before 5pm (South Australia time) Thursday.

"We were called to a reef break just out of Port MacDonnell where we were met there by the family," he said.

"The man could not be located and a large scale search commenced involving police officers, water operations members and the air wing, local state emergency services and fisheries.

"There were also a lot of locals helping with the search, standing upon paddle boards and fishing boats, or standing at shore with binoculars."

Inspector Hill said the police helicopter spotted a great white shark in the area about 8.45pm.

He said the search was called off just before nightfall.

"Up until that point we had recovered two diving fins floating in the water that were believed to belong to the victim," the inspector said.

"We remained hopeful and resumed the search first thing in the morning but sadly we located a wetsuit with significant damage to it, as well as another part of equipment we understand he was using.

"Unfortunately we have put it all together and it certainly paints a picture of a fatal shark attack."

Inspector Hill said no body remains had been located.

He said police believed they had exhausted the parameter of the search area.

"We will revert back to other methods of maintaining eyes on the beach over the next few days," the inspector said.

"This is a really tragic, tragic event. Our thoughts are with the family."

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