Toddler was playing with her 10 siblings on their boat before found face down in Hawkesbury River

The tight-knit community of Brooklyn and Mooney Mooney are mourning the death of three-year-old Zeinobiyah Soetekouw, nicknamed Zobbie, after she was found floating in the Hawkesbury River earlier this week.

The three-year-old girl at the centre of a tragic drowning on the Hawkesbury River on Tuesday was playing with her 10 siblings on their yacht before she went missing.

The toddler, Zeinobiyah Soetekouw, nicknamed Zobbie by parents Steve and Beccie, was on the Sumbawa — the 7m yacht which the Soetekouw family had called home for two years. Beccie went ashore while the yacht was moored in Dead Horse Bay off Brooklyn on Tuesday but when she returned, realised her second-youngest child was missing.

Zobbie was found in the water about 100 metres from the boat, where she had been floating for about 20 minutes.

Zobbie was one of 11 children living on the 7m yacht with her parents. Picture: Supplied

Zobbie, 3, was playing with her 10 siblings and parents. Picture: AAP Image/Julian Andrews

She was pulled from the water by police and taken to Deerubbun Reserve at Mooney Mooney, where paramedics took over and tried to save her. She was then flown to The Children's Hospital at Westmead in a critical condition.

However, she was pronounced dead after arriving at hospital.

Robert Biegalke, who witnessed paramedics trying to save the girl on the wharf at Deerubbun Reserve, said he realised something was wrong when he saw a low-flying helicopter.

“I had a look around and that was when the police boat came rushing into the boat area.

Paramedics work on the three-year-old after she was pulled from the water. Picture: TNV

“Virtually at the same time a flood of police vehicles and ambulances arrived. It was incredibly busy.”

He said the girl was quickly moved from the police boat onto the wharf and a paramedic spent about 30 minutes trying to revive her.

“Paramedics were working on someone straight away. You could see the paramedics just endlessly giving CPR ... it just felt too long to be good.”

She was flown to hospital but died on arrival. Picture: TNV

A worker in Mooney Mooney, who did not want to be named, said she heard emergency services and the rescue helicopter but had no idea what was happening.

“We heard them here from the club but we had no idea what was happening,” she said.

“We saw the Marine rescue boys who moor at our jetty but they are often out on the water so we did not think much of it.”

She said she only found out what happened when she heard it on the radio.

Dangar Island on the Hawkesbury River near Brooklyn Picture: AAP Image/Troy Snook

Hornsby councillor Nathan Tilbury said: “I am unaware if the family was local, but safety on the Hawkesbury is one of council’s major concerns … a beautiful day turned into a nightmare for one family and the entire community is heartbroken to hear of their loss.

“One of the things that makes us such a strong community is the fact that we all come together in a time of crisis and no matter where these people are from, we are here for them.”

It was not known whether the girl was wearing a lifejacket. A report will be prepared for the coroner.