A child has died after the hole she was digging on a beach collapsed on top of her in South Florida.

The girl, thought to be seven years old, was digging the 1.8-metre deep hole with an eight-year-old boy when it collapsed in on them both, authorities said.

Beachgoers were reported to have started trying to dig the children out of the sand before emergency services arrived.

“You saw grown men digging with shovels and buckets and nobody could find her,” a witness told a local news outlet.

When emergency personnel responded to the incident at Lauderdale-by-the-Sea around 3pm they found the boy buried up to his chest in sand, said Sandra King, spokesman for Pompano Beach Fire Rescue.

Ms King told a local media outlet that the girl was completely buried underneath the boy when help arrived.

Rescuers were said to have used support boards to keep the sand caving in anymore as they used shovels to try and dig the children out.

When the girl was uncovered she didn’t have a pulse, Ms King said, adding that it was “an unfathomable accident”.

The boy was rushed to the nearby Broward Health Medical Center while paramedics attempted to revive the girl but they were unsuccessful.

“We were conducting life-saving techniques to try to bring her pulse back, and it never did recover and she was pronounced dead at the hospital.”

The boy is said to be in a stable condition.