Tuition used to be seen as extra help for struggling students, but is increasingly being viewed as a necessity for students to do well in school - further fuelling demand for it here.
Parents and tuition centres said that the extra hours and greater individual attention in smaller classes in the tuition centres provide students with a greater edge in Singapore's competitive education system.
These have become especially important as the school syllabus has become increasingly challenging, they said.
At a youth dialogue about a week ago, Prime Minister Lee Hsien Loong warned against the reliance on tuition, saying: "We are doing too much tuition in Singapore."
While tuition can help if students are really struggling with a subject, teachers should be generally able to help most students through regular classes and, if necessary, extra lessons, he said.
He acknowledged that Singapore's competitive system was partly responsible for the tuition boom, noting that parents are anxious about their children and, sometimes, the children themselves ask for tuition.
The number of tuition centres and enrichment centres registered with the Ministry of Education has jumped from about 700 in 2012 to 800 last year, and 850 now.
Tuition centres interviewed by The Straits Times reported increases of between 10 per cent and 30 per cent in student intake from last year. Some have even seen their numbers double, with the opening of new branches.
Mr Neo Zhizhong, co-founder of Beautyful Minds, a tuition centre with several branches, said: "Parents don't necessarily want their children to do well for their own sake. Sometimes, they simply want their children to do better than others.
"If my son scored 98/100, but someone else's daughter has 99/100, then it's time for tuition."
Ms Sharlyn Neo's 14-year-old daughter goes to Ezybox Learning Hub for six hours of English, science and mathematics tuition a week.
"It's very difficult for students to do well without tuition. The tutors are able to better help with the extra analytical and challenging questions that pop up in the exams," said the 46-year-old housing agent.
But even the tuition centres do not encourage too much tuition.
Mr Jeremy Neo, founder of tuition centre The Classroom, said: "I often advise my students not to go for tuition for more than three subjects. They won't have time to do anything else if they are coming to the centre four times a week," he said.
Dr Jason Tan, an associate professor in policy and leadership studies at the National Institute of Education, who has done studies on the impact of tuition, said that what makes up "too much" tuition depends on the individual student.
"There is a legitimate concern when students spend long hours at tuition and do not have enough time to enjoy life," he said.
However, he added that parents who send their children for tuition may not always be motivated by grades.
"They might be searching to provide for their children something extra, beyond what mainstream schools can offer, such as increased self-confidence or personal guidance," he said.