Shaun Oliver, 32, was visiting the Illawarra on business when he went for a walk on the beach late Sunday afternoon, just as four children were getting into trouble in the waves. 

The children’s father helped two of them to shore, however the eldest, aged 10 and 12, became caught in a rip. 

An off-duty paramedic left his wife and his own young child on the sand in order to bring the 10-year-old boy ashore, said Detective Inspector Brad Ainsworth, of Wollongong Local Area Command. 

Mr Oliver got into trouble as he attempted to rescue the 12-year-old boy. 

Surfers ultimately came to the boy’s aid. Meantime, Mr Oliver was swept out to sea.

Three police officers later stripped off their uniforms and pulled him to shore, where paramedics tried in vain to revive him. 

He was later pronounced dead at Wollongong Hospital. 

“It’s a heroic act,” Det Insp Ainsworth said. “It’s unfortunately cost him his life.” 

The stricken children and their father were visiting the unpatrolled beach from their home south of Wollongong. 

Read more: Most people can’t spot a rip. Can you?

Addressing reporters on Monday morning, Det Insp Ainsworth expressed frustration at the loss of life. He described surf conditions at the time as “treacherous” and confirmed the beach was closed when the family entered the water.

“There was a heavy surf, there was a drag, there was an undercurrent - there were all the conditions there that you don’t go in,” he said. 

“It’s a tragic loss of life and, not putting too much of a point on it … it really puts individuals that come to the aid of people there in danger, and it's the ultimate sacrifice, I suppose.”

“We haven’t even reached the swimming season yet. Unfortunately it’s a timely reminder and warning that you swim between the flags, at patrolled beaches only.”

Mr Oliver leaves behind a wife and three young children. 

He was employed as project manager at a company in Lynbrook, in south-east Melbourne, and was a shopfitter by trade.

​In a Facebook comment, his sister Clare Murray wrote "we are all shattered".

"My brother... the ultimate hero. We cannot believe this has happened... a loss that will be felt by many," she wrote.

Mr Oliver’s cousin Nathanael has launched a Gofundme campaign aimed at supporting the 32-year-old’s grieving family.

”He was faced with the terrible decision when he heard the cries for help and, without a thought for his own safety, launched himself into the water,” Nathanael Oliver wrote. 

His aunt and uncle, Gary and Karen Oliver, said they were “so very proud, and so very sad” at their nephew’s actions.  

He attended Chandler High School in Keysborough, graduating in 2002.

School friend Joel Tranquille said "he was a great friend to everyone, you wouldn't be able to find a single person that would tell you otherwise."

"It's never easy when you hear about a friend passing when he is still so young, especially a great bloke like Shaun," Mr Tranquille said.

Another high school friend, Lisa Pountney, said Mr Oliver "would talk to everyone even socially awkward people".

"(He) would make you laugh or smile if you were sad, he would always put others before himself, he was a bright and loveable guy," she said.

His former sporting club, Keysborough Football Netball Club, tweeted "devastating news that our former junior and senior player Shaun Oliver drowned trying to save two young children in Woolongong".

The emergency unfolded about 4.30pm on Sunday, almost two weeks before patrols at the beach will get underway as part of the 2017/2018 patrol season. 

The off-duty paramedic and two children were transported to Wollongong Hospital for assessment, but did no require admission.

Lachlan Pritchard, Surf Life Saving state duty officer, said authorities had issued a hazardous surf warning on Friday, and that conditions had eased by Sunday but were still considered dangerous. 

“It can be quite deceiving, the surf conditions,” he said. 

“While the waves might not look too big, the undercurrent … is quite strong and that’s what does cause most of the issues. The conditions can sweep you right out.

“If you do get stuck in a rip, we encourage you to raise your hand to signal for help and ride the rip out to the back where there is calmer water and hopefully wait for emergency services to arrive.”  

Surf lifesavers are urging swimmers to heed the “no flags, no swim” message, as summer approaches. 

- with The Age