Nearly 60 000 people crossed the Beit Bridge border post in a 24-hour period last week.
This is according to the Department of Home Affairs after complaints of long waiting periods, chaotic queues and understaffing at the border post.
Thousands of people travelling back into South Africa had arrived at the border late evening on January 3 and were only assisted the next day.
Scores of people sat in long snaking queues waiting to be served by South African immigration officials. Others sat around the immigration area with their belongings and slept there the night.
GroundUp spoke to people who had waited several hours to be seen by an immigration officer.
One woman who had arrived at 23:00 said her brother was waiting for her on the other side of the border to drive her back to Johannesburg. She was only assisted after 09:00.
Another Zimbabwean woman said she had left her baby with her husband. She went to buy goods and did not expect that it would take that long when returning. It is unclear when she was assisted.
When GroundUp arrived, only one immigration officer was processing and assisting people. During previous visits, five immigration officers were there to serve people travelling into the country. More staff only arrived at 07:00 January 4.
By then, travellers were exhausted and had begun shoving and pushing to get to the front to be served. One staff member tried to keep people calm but they did not listen.
After about 30 minutes of chaos, several police officers arrived. They ordered the group to stand in three lines.
People endured scorching temperatures and were only served by midday on January 4.
Siya Qoza, spokesperson for the Minister of Home Affairs, said 51 immigration officers were meant to be on duty at all times. He said 29 832 people had crossed the border on 3 January. The next day, 53 immigration officers were on duty and 30 137 people crossed into the country, he said.
When asked why more staff were not sent to assist during one of the busiest periods, Qoza said he could not respond to this.