The death toll from a building collapse in South Africa climbed to 20, municipal authorities said Sunday, with 32 people still unaccounted for nearly a week after the structure came crashing down.

Rescue teams have been working tirelessly since an apartment block under construction in the southern city of George crumbled Monday afternoon while a crew of 81 were on site.

Twenty-nine people have been rescued alive so far.

On Saturday an unexpected survivor emerged after 116 hours from underneath the rubble of the collapsed building, municipal authorities said.

Provincial authorities described it as a "miracle" as they rushed against time with rescue efforts.

"The question of rescuing... and recovery is still mixed, people feel that they still need to go very slowly especially with what happened yesterday," Police Minister Bheki Cele told state broadcaster SABC during his visit to the site.

Family members housed in a nearby city hall since Monday expressed their frustration to the police minister at the pace of the identification process.

Premier Alan Winde of the Western Cape province had previously said the process had been "difficult".

Police were using fingerprints, DNA testing and photographs.

Previously authorities declined to comment on speculation about whether most of the crew were foreign nationals.

However the government said it would contact the diplomatic missions of Mozambique, Zimbabwe and Malawi regarding the incident and have issued a call for a "psychosocial support practitioner proficient in Chewa, Portuguese, and Shona languages to assist survivors and their families".

Construction plans for a 42-unit apartment block had been approved by the city in July.

The reasons for the collapse are still unknown.