Amid a separate search in Palm Beach, authorities also continue to search for a man in his 20s who disappeared in rough swell at Coogee Beach. (ABC News)

The identity of one of four people who died in a cluster of drownings on the New South Wales coast in recent days has been confirmed as a Sydney hairdresser and mother.

Surf Life Saving NSW performed more than 85 rescues between Christmas Day and New Year’s Day.

Treacherous surf conditions have closed about 70 beaches across the state, with NSW Police confirming a fourth person drowned on Friday afternoon at a beach on the south coast.

On Thursday, Berowra Heights woman Melissa Austin died at Dunbogan Beach in Camden Haven on the Mid North Coast in a suspected drowning.

Ms Austin was attempting to save her child from a rip when she herself got caught in the dangerous swell.

Members of the public provided first aid until emergency services arrived, but the 45-year-old could not be revived.

Flowers and candles can be seen inside Ms Austin’s salon in Berowra Heights. (ABC News: Isobel Roe)

Ms Austin’s salon in Berowra Heights in Sydney’s north was closed on Friday.

Her friend Brett Nipper said the tight-knit community was in disbelief over Ms Austin’s death.

“Everybody knows her in Berowra, she’s part of the fabric of the place,” he said.

“She’s the sweetest lady, you ask anybody around here, and they’ll tell you the same. She’s going to be missed.”

Dunbogan Beach rock fisher Chris Lane says the beach has a dangerous undertow. (ABC Mid North Coast: Marina Trajkovich)

Local fisher Chris Lane was near Dunbogan Beach when emergency services arrived on Thursday.

He said it was not safe enough to climb the rocks at the time as the “surge was waist-deep on the beach”.

“It has a really strong undertow, so in a big ground swell like we have here, you’ve got to be really careful.”

Rescue operations centred on the northern end of Dunbogan Beach, an area known colloquially as ‘Southies,’ south of Dunbogan Head. (ABC Mid North Coast: Marina Trajkovich)

Flagged down on the road behind Dunbogan Beach, ice cream vendor Kurtulus Elma was quick to call an ambulance to the scene.

“An early 20s young man stopped me — he was really panicked and nervous and said he was on the phone to the police,” Mr Uluselma said.

While Mr Uluselma called Triple Zero (000) and gave directions for an ambulance, a boy ran onto the road from the beach.

“He was eight to 10 years old, and he was really scared and panicked.

“I hold him because he was going to the road, [so] I look after him and try to make him calm down.”

The  local ice cream mobile vendor contacted the ambulance when stopped by a man on the road behind Dunbogan Beach. (ABC Mid North Coast: Marina Trajkovich)

Mr Uluselma waited for the boy’s family and then directed ambulances and police to the rescue location.

“She lost her life, and I’m so sorry about her and her family.”

Search resumes for missing teen

Another incident occurred at the northern end of Palm Beach on Wednesday, when a boat carrying two men and a 14-year-old boy capsized and crashed into rocks.

Emergency services rescued one man, while another was pulled from the water unresponsive and died at the scene.

A large-scale search for the teenager has now entered its third day.

The incident occurred at Palm Beach, on Sydney’s northern beaches. (ABC News)

Authorities also continue to search for a man in his 20s who got into difficulty while swimming with friends at Coogee Beach on Thursday morning.

A uniformed police officer and two off-duty surf lifesavers entered the rough surf and rescued two other men.

The search is continuing at Coogee Beach, which remains closed to the public. (ABC News)

On Friday morning, police divers were seen circling the area where the man was last seen, focusing on an area where a pool of green dye appeared to have been released.

Authorities are also searching the area on jet skis with assistance from the Westpac Lifesaver Rescue Helicopter overhead.

Coogee Beach was closed due to hazardous surf on Thursday. (ABC News)

Conditions have eased overnight, but rescue crews continue to battle rough swell close to shore.

Crowds of people could be seen watching on from outside the beach, with a plane carrying a beach safety banner reminding people to wear life jackets while out on the water.

Beach safety warning

Earlier on Thursday morning a 25-year-old woman also drowned after she was swept off rocks and knocked into a tidal pool at Maroubra Beach.

Surf Life Saving NSW chief executive Steven Pearce said all drownings occurred at unpatrolled locations during hazardous conditions.

“Really, it’s been left up to members of the public to try and assist in the first instance,” he said.

“The drowning really tragically yesterday afternoon at Dunbogan Beach of a mother, again members of the public raced to her aid and commenced CPR until we could get our nearby lifesavers from other beaches there to assist.”

A 25-year-old woman was swept off rocks into a tidal pool at Maroubra Beach. (ABC News)

Members of the public also provided assistance to a man who was knocked unconscious after performing a backflip off a pier at Shoal Bay.

Mr Pearce said that incident could have resulted in fatalities had first responders not been equipped to provide emergency aid.

“Fortunately there [were] other people there to dive in. He was unconscious in the water and if not for their actions, potentially that could have been another drowning,” he said.

Beachgoers are being urged to swim between the flags this summer. (ABC News: Kathleen Dyett)

“We’re really pleading with people for the remainder of summer, if you are going to go down to the beaches … it’s so important to find a location were there are lifesavers and life guards on duty.

“Every drowning that has occurred in the last 12 months has all been at unpatrolled locations, away from those red and yellow flags.”

The majority of beaches have now reopened, although Coogee Beach remains closed.

The Bureau of Meteorology has cancelled its hazardous surf warning for much of the coast, although a strong wind warning remains in place for Eden on the Sapphire Coast expected until Saturday.