ULSAN, South Korea - Police have arrested a childcare teacher for abusing a toddler by shoving tissues into his month, Yonhap News Agency reported on Tuesday, a week after the nation was shocked by another case of child abuse.

The teacher in her 40s allegedly stopped the 22-month-old boy crying by forcing tissues and towels into his mouth, the Ulsan Metropolitan Police Agency said.

She was believed to have repeatedly done so from November to December in a daycare centre she owns in Ulsan, 410km south-east of Seoul.

The woman said she found the boy annoying as he cried too much, a police source told Yonhap.

The arrest came after footage from security cameras showed another nanny punching a 4-year-old girl at a daycare centre in Incheon, west of Seoul.

The 33-year-old, known only as Yang, admitted last week that she had punched the child, but she claimed that the act was part of discipline measures to correct the child's bad habit, investigators said.

The Incheon incident caused a national uproar, with the government unveiling new measures to shut down daycare centres that are found to have abused children.