A seven-year-old girl has died at an Ekurhuleni boarding school, apparently because of food poisoning, the Gauteng health department said.

The girl was one of 26 boarders at the Aurora Comprehensive School affected by what the department described as a "suspected food poisoning outbreak".

"On April 18, 11 pupils complained of a headache, stomach ache, nausea and vomiting," department spokesman Chris Maxon said in a statement.

"The children were [then] sent to [nearby] Arwyp Hospital, where four were admitted and six were treated and sent back to the school."

The girl died on April 19 on the school grounds. After her death, another 15 pupils were sent to Tembisa Hospital, where one was admitted and 14 discharged.

The Wits Medical School was investigating.

"Samples [of food] are still at Wits's NHLS Infection Control Services Laboratory for chemical and bacteriological analyses," Maxon said.

A team of Ekurhuleni officials visited the school.

"When the outbreak team [arrived], there was no food left over from the night of April 18. However samples of food left over from breakfast on April 19, and water from the borehole used by the school, were collected," Maxon said.

The department was still awaiting the results of laboratory tests.