ALARM bells went off when a child discovered nests of eggs in a New South Wales school sandpit - but what species they belong to is a mystery.
Wildlife volunteers at Fawna, who spent three days digging up the seven nests and 43 eggs on the state's mid-north coast last month, said they have started to hatch.
The group believes the eggs, discovered at Laurieton near Port Macquarie, belonged to the extremely venomous eastern brown snake.
However, Australian Reptile Park general manager Tim Faulkner told the Daily Telegraph the shape of eggs found in the sandpit were not consistent with the more elongated size of the deadly brown snake.
"I can say with a high degree of certainly the eggs look like a water dragon lizard eggs," he told the newspaper.
"The fact the school is near the water also makes it more unlikely to be an eastern brown snake, as they are not so active there.
"Another thing is that brown snakes just don't have legs, and these eggs were buried - brown snakes more commonly use an existing rabbit warren or under timber."
But, this morning, the mystery deepened further as Fawna released a statement saying it is "fairly certain" it is dealing with snake eggs - "possibly" from an eastern brown.
"Due to the fact of all of the controversy I went back and checked on the nest and found that all but one of the eggs had hatched," the statement read.
"The remaining egg contained a small pink wormlike embryo with two eyes and no sign of legs.
"It may or may not have been a snake but the good news is that all animals have been released and living in the wild."
Volunteers for the wildlife group visited the sandpit the day the call came in - on December 20 - and removed 12 eggs.
But, that same afternoon, more eggs were discovered buried in another part of the pit.
Yvette Attleir, a Fawna Wildlife Rescue volunteer, said the group cordoned off the pit to thoroughly search the area and remove the eggs.
The Fawna statement also responded to the criticism and comments coming through on social media.
"We really don't have the time or the people power to deal with all the comments coming through at the moment, we are a small, time poor group of volunteers in a very busy time of the year. We always appreciate constructive input from the public,"
"If you would like to join FAWNA please see our website as we would love to have more members on the ground helping our stretched volunteers, especially at this time of the year."
Ms Attleir believes the nests and eggs could have all been laid by a single brown snake.
She said the snake could have snuck into the sandpit shortly after it was constructed.
"The sand was still fresh and loose and would have provided the perfect place for snakes to regulate the eggs due to the temperature," she said.
"The pit also backs on to a reserve so it would have looked like the perfect nesting place for the snake."
Once the eggs are laid by the mother, the baby snakes are then left to hatch independently.
Despite the shocking discovery, Ms Attleir said there is no need for nearby residents to be overly concerned.
"We live in an area where we are surrounded by a lot of nature, which is wonderful," she said. "Dealing with nature is a natural part of life here."
She added that the eggs were carefully removed and safely placed at an unspecified location.