Wildlife volunteers were called to the school after a child noticed some mysterious looking eggs while playing in the pit.
After three days of digging at the Laurieton school the wildlife team discovered seven nests and a total of 43 eggs from the extremely venomous snake.
Yvette Attleir, a Fawna Wildlife Rescue Volunteer, said: 'Even when they are newly-hatched, brown snakes can still be very dangerous to humans.
'The venom is not quite as potent as it would be in an adult snake, but if a child was bitten then they would have to go straight to hospital.'
The Fawna Wildlife volunteer believes the nests and eggs could have all been laid by a single brown snake, claiming the snake could have snuck into the sandpit 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.'
Despite the shocking find, Attleir claims that nearby residents should not be concerned.
'We live in an area where we are surrounded by a lot of nature, which is wonderful,' she explained. 'Dealing with nature is a natural part of life here.'
She added that the eggs were carefully and safely removed.