Many are thought to have been students celebrating the end of their high-school exams on Saturday night, provincial officials said.

Officials have ruled out a stampede as a possible cause and said autopsies would determine if the deaths could be linked to poisoning.

Crowds of people, including parents whose children were missing, gathered on Sunday outside the tavern where the tragedy happened in the city of East London while mortuary vehicles collected the bodies, an AFP correspondent saw.

"We have a child that was there, who passed away on the scene," said the parents of a 17-year-old boy.

This was a humble child, respectful," said grieving mother Ntombizonke Mgangala, standing next to her husband outside the morgue.

He voiced concern "about the reported circumstances under which such young people were gathered at a venue which, on the face of it, should be off-limits to persons under the age of 18.".

"You can't just trade in the middle of society like this and think that young people are not going to experiment," he said outside the tavern, in a residential area called Scenery Park.

Empty bottles of alcohol, wigs and even a pastel purple "Happy Birthday" sash were found strewn on the dusty street outside the double-story Enyobeni Tavern, according to Unathi Binqose, a safety government official who arrived at the scene at dawn.

Local television showed police officers trying to calm down a crowd of parents and onlookers gathered outside the club in the city, which is located on the Indian Ocean coast, around 620 miles south of Johannesburg