South Africa has relaxed requirements for Zimbabweans to get permits to stay in the country as thousands queue at government offices.
They have to get correct paperwork before a new year deadline, otherwise they will face deportation.
Officials now say that passports are no longer required and those still in the queues by closing time will be seen.
Some two million Zimbabweans are estimated to be in South Africa, many of them illegally.
They have been fleeing recent instability and economic crisis in their own country.
Slow and bureaucratic
In September, Zimbabweans working illegally in South Africa were told they had an opportunity to be processed and, if successful, given work visas and residency to stay.
After midday on Friday some 230,000 people had taken advantage of the amnesty and applied across South Africa in what correspondents say has been a painfully slow bureaucratic process.
So far 38,000 applications have been approved, while another 6,000 have been rejected, according to the Home Affairs Department.
Applicants have had to present their Zimbabwean passports, their birth certificates and letters from their employers or affidavits from the police to prove self-employment.
But many of the migrants crossed into South Africa from Zimbabwe illegally - without passports.
Mkhuseli Apleni, director general of the Home Affairs Department, said this requirement had been dropped to encourage more people to apply and speed up the registrations.
"At the first day they said they wanted passport, now other ID is acceptable, that's why there are so many of us like this at the last minute," Judith, a Zimbabwean waiting in a queue outside a Home Affairs office in Johannesburg on Friday morning, told the BBC.
Another man who joined the queue at 0530 local time said, "I lost my passport, so I came today when I heard they were taking birth certificates."
Fake papers arrest
Mr Apleni also said all those in the queues would be seen even after the offices closed at 1700 local time.
"We will endeavour that those who remain on the queues at the close of business today are indeed served," he said in a statement.
"We reiterate our view that there has not been any discussion in cabinet about extension of the deadline."
The BBC's Nomsa Maseko in Johannesburg says that, given the length of the queues, the process could last well into the night.
Meanwhile, a Zimbabwean man has been arrested for allegedly supplying fraudulent documents to his fellow countrymen who were standing in queues waiting to be processed in Pretoria.
Authorities say the fake papers he was selling include letters of employment.