Autopsies have been performed on the 21 teenagers who died in an unexplained incident at an East London pub on Sunday, says the Eastern Cape government.

The Eastern Cape government in a statement said samples have been sent to a lab in the Western Cape for investigation.

Provincial government spokesperson, Khuselwa Rantjie, said the report will be shared with the affected families as soon as investigations have been concluded.

"The South African Police Service (SAPS) remains on the scene and continues to comb the scene for further clues in relation to the tragic incident."

Meanwhile, Rantjie said, engagements between government and the families determined that a mass funeral service will be held next week Wednesday.

"Thereafter, families will be assisted with transportation of the remains to be interred at burial sites of their choice.

"Government has expressed appreciation for support that has been received from all sectors of society in preparation for the funeral. Amongst those is AVBOB. The funeral palour has pledged burial costs support for each family."

The Buffalo City Metropolitan Municipality (BCMM) has waved the grave fees for the burial of the deceased and together with the provincial government, will facilitate other logistical needs to ensure a dignified send-off for the deceased.

Rantjie said food parcels and vouchers were on Wednesday morning delivered to assist with immediate needs of the families.

"The provincial government, together with its partners, will continue to provide psycho-social support to the bereaved families and the broader community. This will include community debriefing sessions to assist everyone to cope with the impact of Sunday's tragic event," she said.