Mr El Kourouche went fishing off the Illawarra coast on Saturday, leaving from the Bellambi boat ramp around 1.30pm.

The boat he and two friends and a five-year-old boy were in capsized off Bulli Point.

The two male friends were saved but the body of the boy was found in the boat earlier on Sunday.

Acting Wollongong Police District Commander Brad Ainsworth said it was unlikely they would find Mr El Kourouche alive.

"I can't see anything positive coming out of it, unfortunately," Commander Ainsworth said.

"He's been in the water for 12 hours-plus. It's a sad reality, unfortunately. I would love to be wrong but I would be thinking at this stage we're just hopeful of retrieving [a body]."

Commander Ainsworth said there was speculation of a reef off the Bulli coast and the boat hit that and capsized.

He said that would form part of the police investigation, along with navigation skills of those on board and whether lifejackets had been worn.

9.20am: The body of the five-year-old boy missing off the coast of Bulli has been found. Read the full story here.

9am: The sister of the man missing in waters off Bulli Point said he was trying to save the life of the five-year-old child on board when their boat capsized.

The missing man is Saadallah El Kourouche, 28, of Carnes Hill in western Sydney.

He had gone out fishing at around 1.30pm with two friends, who were the men rescued on Saturday night.

The five-year-old boy who is also missing is the son of one of the rescued men.

Mr El Kourouche's sister Hayat said she had spoken to one of the rescued men last night, who told her the boat capsized after it hit a rock.

"One of the guys that were rescued, I called him up," Ms Kourouche said.

"He told me that the boat flipped and that they were all drowning. The five-year-old was caught in the boat and my brother was trying to rescue the kid."

The friend told Ms Kourouche that he found her brother floating face-down in the water.

He turned him over onto his back but soon lost him in the darkness.

She said her brother had three young daughters and the family was waiting at home for news from the ongoing search at Bulli Point.

"We're just hoping for a miracle," she said.

"We're just sitting here trying to be strong and hoping he comes home for his kids."

Mr El Kourouche's wife Samah said she didn't know her husband had planned to go fishing on Saturday.

She described him as a "very humble, friendly man".

"A loving person, he always puts other people before him," she said. "He's a very good person."

7.50am: The search for the two people missing from the capsized boat resumed off Bulli Point at 7am on Sunday.

The search was suspended at midnight last night due to the conditions.

Police have said the missing people are a five-year-old boy and a 28-year-old man.

The two people rescued last night were males, aged 23 and 31.

Saturday night: A major search is underway off Bulli for two occupants - including a child - who were on a boat that is believed to have capsized.

Two people have been rescued but the child and an adult are still missing, with rescuers reporting hearing calls for help from the darkness.

Police have not been able to confirm the age of the child, who is believed to be a boy.

At around 10pm a crew from Marine Rescue Port Kembla towed the capsized boat to shore.

Earlier on Saturday, at around 6.20pm officers from Wollongong Police District were called to Bulli Point, off the rock pool after a boat capsized.

Toll ambulance rescue helicopters were called to search the waters off Bulli, joined by members of Surf Lifesaving Illawarra.

"During that search they located two persons in the water, alive but very cold and exposed to the elements," said Chief Inspector Brown from Wollongong Police District.

"They recovered those people and brought them to shore. They have since been taken to Wollongong Hospital."

The rescued pair were two men in their 30s.

At this stage, it is not known whether the four people on the boat were from the Illawarra or were visiting the region.

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Chief Inspector Brown said the overturned boat was about 4-5 metres in length and appeared to be a "fishing vessel".

"We don't what happened to cause the boat to capsize," he said. "We have no idea.".

Marine Rescue's region operations manager Bruce Mitchell said a member of the public raised the alarm about 6.45pm Saturday.

"They said said they'd heard voices out in the water, calling out for help," Mr Mitchell told the Mercury.

Two police aircraft - a chopper and Cessna - are circling an area off Waniora Point.

Water Police and Marine Rescue NSW boats are also searching, with surf lifesaving resources.

More to come.

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