The 44-year-old warden, who is also a secondary school senior assistant, was picked up after the girls - aged 15 and 16 - lodged reports on Wednesday.
Acting district police chief Asst Supt Tan Yong Soon said the suspect has been remanded for a week under Section 376 of the Penal Code to facilitate investigations.
He said the two girls would be referred to the Likas Hospital for medical examination.
ASP Tan said the younger victim, a Form three student, claimed that she was raped during the wee hours of Nov 7 last year while the Form Four student claimed she was raped sometime around midnight in February this year.
Earlier, the girls were scared and frightened to report the rapes, he said.
He urged rape victims to lodge reports immediately as it would make it easier to nab the culprit. - Source