A new South African law has taken effect, meaning parents who do not pay child maintenance can be put on a credit blacklist to prevent them getting loans.
Critics say the law will make life even more difficult for those on low wages.
But the government says it will force those who do not support their children financially to take action.
After an outcry, the clause was removed before being reinstated and now signed into law by President Jacob Zuma.
Pumza Fihlani in Johannesburg says among the critics of the bill is the Economic Freedom Fighters opposition party, many of whose supporters are low-income workers.
Many people in South Africa, especially the poor, rely on credit to survive, she says.
In June, Deputy Justice and Correctional Services Minister John Jeffrey is reported as having said to the National Assembly that by restricting maintenance defaulters from getting credit, they will see the urgency of looking after their dependants.
The clause in the Maintenance Amendment Act proved controversial, and was taken out of the bill earlier in 2015.
But it was reinstated in May when no viable alternatives were put forward.
The opposition Democratic Alliance welcomed its re-inclusion.
"This is a victory for thousands of children who suffer because their parents could not care less about supporting them financially," they said.