Friends and family of shark-attack victim Adam Strange braved the surf at Auckland's Muriwai Beach this morning in a fitting tribute.

Strange, 46, a film director, was killed by a great white at the beach on Wednesday.

The beach and surrounding regional park was closed after the attack, but re-opened today.

Around 60 mourners, including Strange's widow Meg and mother Jeanette, gathered at the beach where they waded into the water and cast flowers into the waves.

Close friend Johnny O'Leary said Strange would have been "stoked" they had all come together.

"I feel like after what happened with the shark we can't be fearful.

"That's what he would have wanted, he wouldn't want us to be fearful."

O'Leary said he had been close friends with Strange since they went on a group surfing trip to Indonesia together eight years ago.

"Adam would always leave such a big impression, he was such a big presence."

His friend's death had been horrific, he said.

"I was working in the area and came down and saw it all unfold, but I didn't know it was Adam.

"I went down to the car park and saw his car but I couldn't see him anywhere and I thought that was pretty strange - it was pretty horrific."

ATTACK WITNESSES' BATTLE

A 17-year-old volunteer lifeguard is one of dozens of attack witnesses struggling for emotional support to cope with what he saw.

The teen was one of five lifeguards and volunteers - two of the others just 22 years old - who took to the water in inflatable lifeboats to chase off the four-metre great white shark mauling Strange's body on Wednesday afternoon.

The shark, and others, then mauled his body for 30 minutes while lifeguards and police tried to drive them off.

Dozens of witnesses had called the Muriwai surf club seeking support, said club chairman Tim Jago.

"We underestimated how many eyewitnesses there were. My list is growing every day. There were fishers, day trippers who were taking photos at Maori Bay, and people who came from the park because of the sirens and helicopters.

"One eyewitness called just before and asked for the same counsellor we're using because they're not sleeping well."

Some lifeguards were too traumatised to return to the water.

"Some of them are pretty apprehensive," Jago said.

The mother of the 17-year-old who was on the water chasing the shark as a police officer tried to shoot it contacted the club, worried her son would not tell her about the ordeal.

"He's spoken with other males and older males. It's something he wants to 'bloke out'," Jago said.

"He's back helping out."

Jago had the traumatising task of identifying the badly torn body of Strange, a man he dealt with almost daily.

"I didn't want Meg [Strange's wife] to identify him. It was bloody horrific."

Jago admitted he was struggling to get over the attack himself.

''I've had a couple of flashbacks, I have to say. I've never dealt with a shark attack before."

Shark expert and documentary maker Mike Bhana had been brought in by the club to allay fears the great white will return and brief lifeguards before their shift started as the beach reopened.

Bhana's briefing would also allow lifeguards to answer people's questions.

"The public will have a lot of questions. It will be mentally challenging," Jago said.

Dave Walley, a member of the Westpac Rescue Helicopter which hovered overhead as police shot at the shark said he believed the great white was killed.

But Jago said the surf club had spotters at a headland for two days and arranged flyovers from Coastguard and the Police Eagle to monitor for the shark.

Nothing has been seen, he said.

KILL ORDER 'SPLIT-SECOND DECISION'

The call to shoot and kill the shark that attacked Strange was a split-second decision, police say.

Senior Sergeant Scott Webb said the great white reared up as inflatable rescue boats carrying an officer with a M4 bushmaster rifle, approached.

It allowed the officer to shoot two rounds into the back of the white pointer's head, effectively killing it.

"The shark was thrashing the body about, which enabled the officer to shoot it," he said.

The shark was then seen to roll over and slip beneath the water.

Tactical options, which included killing the shark, were discussed by police and Westpac Rescue Helicopter staff before the officer set out.

"But the officer made the call to try and kill the shark to get the body back."

Police spend days working to recover dead bodies to help bring closure to families.

FAMILY TRUST SET UP

Strange's widow Meg is thanking wellwishers for their displays of support, saying the family had been overwhelmed with flowers and gifts.

Family friends have created a trust to help pay for the funeral and support Strange and 2-year-old daughter Indigo.

Donations can be made under the reference 'Adam' into James Bell Accounting Ltd Trust Account through ANZ Bank: 06 0193 0262946 03. 

A funeral for Adam Strange will be held at the Mairangi Surf Lifesaving club rooms on Monday at 3pm.

- © Fairfax NZ News