A relief teacher in a secondary school had sex with his student four times over a period of about a year, a district court heard on Monday.

Ross Ryan Kristiaensen, 30, now unemployed, admitted to two counts of having sex with the minor at his home in 2009 and at her flat in October 2010.

The court heard that he was teaching home economics at the school in 2009 when he became acquainted with the Secondary 1 student.

Sometime in end-June, they went out for lunch and to buy items for a competition organised by a community centre.

After the competition, they became close, sending text messages and calling each other daily.

On Nov 25 that year, the bachelor brought her to his flat. They hugged and kissed. She agreed to be his girlfriend. He told her not to tell anyone that they were in a relationship.

On Dec 3 that year, he had unprotected sex with her in his bedroom. He promised that he would marry her.

On Sept 1, 2010 - Teacher's Day - while was using his laptop at his flat when she came across an online chat that he had with another girl. They had an argument and broke up, but she still had feelings for him and they kept in touch.

On Oct 10, she asked him over to her place when her parents were on an overseas trip. He spent the night there and had sex. She was then 14.

Two days later, he was hospitalised and the victim visited him. Her family missed her for dinner. When they found out where she was, they went there and saw them sitting very close together.

The victim subsequently revealed that she had a sexual relationship with Kristiaensen and lodged a police report on Oct 14. His services were terminated.

He will be sentenced on April 3.