The government said Tuesday it will look into child mistreatment cases at nurseries across the country and how municipalities have handled them, following the arrest of three nursery teachers in central Japan for allegedly abusing toddlers.

The case at the nursery in Susono, Shizuoka Prefecture, which also highlighted the municipality's tardy disclosure and the nursery head's alleged coverups, is "extremely regrettable" and "should not have happened," health minister Katsunobu Kato told a press conference.

Investigators enter a nursery school in the Shizuoka Prefecture city of Susono in central Japan to search the facility on Dec. 4, 2022. (Kyodo)

Police arrested the three women on Sunday on suspicion of committing abuse toward children in June such as hitting the toddlers and hanging them upside down by their feet.

Susono's mayor then accused the head of the nursery of covering up the abuse, suspecting he made all school teachers write an oath to keep the abusive behavior secret and intentionally delayed the announcement of the incident to parents.

The nursery's head also did not report to city authorities or police despite a whistleblower coming forward from around June to July claiming abuse had been committed by some of the teachers, a source close to the municipal government has said.

The municipal government, meanwhile, has faced criticisms for its slow response as it disclosed the case only last week, more than three months after it first received a tip about the abuse allegations in mid-August.

Through the probe that is set to be undertaken soon, possibly by year-end, the central government seeks to get a handle on mistreatment cases at nurseries and see whether municipalities are appropriately responding when they receive tips or hear of allegations.

Related coverage:

Japan city accuses nursery school head of covering up toddler abuse

Japan nursery school teachers arrested over abuse of toddlers

Kindergarten head referred to prosecutors over 3-yr-old dying of heat