Shy and reserved as a child, former Dunman Secondary School student Justin Ng was often teased and called names by his classmates.

"I did not know what my identity was, felt I was rubbish at everything, and was that boy in class who refused to speak up," he said.

But his chemistry teacher, Mrs Vivien Low, encouraged him by providing opportunities to make presentations in front of the school and soon, he discovered a love for public speaking.

Later, he decided to pursue a career in teaching, to inspire others, as Mrs Low had done for him.

Yesterday, the 25-year-old was among the 325 new teachers at the National Institute of Education (NIE) investiture ceremony, held at the Nanyang Technological University (NTU) auditorium.

In a confident and eloquent valedictory speech, Mr Ng - who held leadership roles at Meridian Junior College, NIE and NTU - paid tribute to Mrs Low, who is now the principal of Fengshan Primary School.

"I am grateful to those who have helped me throughout my journey," said Mr Ng, who is teaching English and biology at Springfield Secondary School in Tampines. "I hope to guide students who are like me, in the past, to believe in themselves and discover their potential."

Mr Ng graduated with a Bachelor of Science (Education) and is the only graduate since 2011 to receive five university awards.

Yesterday's ceremony is the first of three in which a total of 1,216 new and returning teachers will graduate. Education Minister Heng Swee Keat, who was the guest of honour at yesterday's event, said teachers must keep learning throughout their careers. "No education system can rise above the quality of its teachers," he said. "To teach well, strive to be the best learner you can be... and raise the generation that will take Singapore forward."