SINGAPORE - A man who accuses his primary school vice-principal of sexual offences against him said he decided to alert police when the alleged abuser refused to settle out of court for $200,000, then accused him of extortion.

The pair, who had previously lived together, met on Nov 24, 2015 - 12 years after the alleged offences began - but instead of reaching an agreement, the vice-principal sent his former pupil a cease and desist order from a lawyer, a court heard on Tuesday (March 27).

On the second day of the 55-year-old teacher's trial, the 29-year-old alleged victim testified that the older man sent him a text message later that day which insulted his parents and told him to lodge a police report.

The younger man, a Singaporean who came here from China in 1999, claimed the man said in the message: "Singapore does not need new citizens like you....I've been so nice to you and you did this to me."

The younger man alerted the police the next day and told the court on Tuesday: "I felt justice needed to be served."

The vice-principal is on trial for three counts of committing an indecent act on a young person and six of having carnal intercourse against the order of nature with the victim when he was a teenager. He has been suspended from his duties.

The man and the vice-principal cannot be named due to a gag order.

On Tuesday, the victim testified that he did not want to inform the police about the case at first due to his responsibilities to the vice-principal's family, adding that he had treated the man's parents like his own grandparents.

The victim told District Judge Chay Yuen Fatt that he had helped in taking care of the older man's ill parents and his alleged abuser was also supporting the family financially.

Wiping away tears, he added: "If I reported, the whole family dynamics would change because (the vice-principal's) job would be affected."

The court heard that the victim met his future wife, also a Singaporean, while on a group tour to Europe with the vice-principal in June 2013. He continued contacting the woman when they returned home and they entered into a relationship.

He later told her about what the vice-principal had allegedly done to him. She advised him to move out from the home they shared and inform the police.

The man moved out in 2013 to the woman's family home after lying to the vice-principal that his parents knew about the alleged sex acts.

He told Judge Chay that the vice-principal was apologetic when he heard this and told him: "Please don't report to the police. Otherwise, I would commit suicide."

In August 2015, the younger man bumped into the vice-principal's niece - someone he knew had dealt with sexually abused children in the past.

He decided to tell her about what her uncle had allegedly done to him.

The victim testified that the niece then told him to alert the police and added: "She said that whether her family dynamic was destroyed or not was not my concern...This encounter lifted the guilt from me as to why I left the family. There was an option for me to report to the police but I was not ready."

He later thought that it would be a good idea to try settle the matter out of court without informing the police by asking for the $200,000 compensation.

He contacted the vice-principal who agreed to meet him on Nov 24, 2015. When they met at a cafe, he said that the older man told him that somebody would send him the money and left. The victim testified that a man came forward shortly afterwards to hand him the lawyer's cease and desist order.

The trial resumes on Wednesday.