The childcare teacher who allegedly dragged a three-year-old boy across the floor and caused him to fracture his shin has 16 years of experience in the preschool sector.

The 51-year-old was working as a part-time teacher at the NTUC My First Skool childcare centre in Toa Payoh when the incident happened on July 5.

She was a "qualified diploma trained teacher" who joined My First Skool in 2009 from another operator, who had not had any prior complaints, said Ms Geraldine Lee, chief human resource officer of NTUC First Campus, which runs My First Skool, at a press conference on Sunday.

Chief executive officer Chan Tee Seng said: "I watched the video last night and was very disturbed and saddened. The teacher's conduct was totally unacceptable."

Mr Chan added that more staff will be asked to man a dedicated hotline at 6634-9989 to address parental concerns, and NTUC First Campus will "step up engagement and training of our staff to reinforce the right conduct, behaviour and good practices".

Meanwhile, a "due process" is underway, with the teacher involved being called to a face-to-face meeting with the management on Monday, which could result in her dismissal, said Ms Lee. But Ms Lee also stressed the need to be fair to the teacher.

According to Mr Chan, the boy's parents had requested for him to be transferred to another school under the NTUC First Campus umbrella.

NTUC First Campus will continue to provide full cooperation to the relevant authorities which are investigating the incident.