Students at the opening ceremony of the annual Pre-University Seminar did not hold back from asking tough questions.

Temasek Polytechnic student Ashley Liao, 19, who was among the 550 students from the 34 institutions represented, asked Senior Minister of State for Education, and Communications and Information Janil Puthucheary about the need for an ethnically reserved presidential election.

Changes to the Presidential Elections Act were passed by Parliament in January, reserving the September contest for candidates from the Malay community.

Ms Liao asked: "Do you think that it is problematic that we've had to make use of affirmative action in order to have representation in our presidential office?"

Dr Janil replied that Singapore will not need the racially reserved presidency when Singaporeans are race-blind and all underlying related tensions no longer exist.

"If all those disappear, we will not need a racially reserved election. The problem is that they are present. And we are worried that given that they are present, it would not be possible for a minority president to be directly elected," he said.

He added that the racially reserved presidency is "not a nice solution that we would wish on Singapore after 52 years of independence".

"Wouldn't it be great if we never had to have it? But it's a marker of what we still have to solve. In my generation and yours."

He also reminded students of the sunset clause in the Constitution - if a minority president is elected in an open election, the racially reserved presidency will not need to happen.

But Dr Janil said he believes the sense that race truly does not matter anymore does not come when a minority candidate wins an open election. Instead, he explained that "it will come when he loses in an open election and everybody says it has nothing to do with his race, he just wasn't the best man".

Ms Liao later told The Straits Times that she wanted Dr Janil's opinion as he is a politician from a minority race. "I wasn't expecting such a direct answer... He gave me a relatively satisfactory answer."

Yap Ching Yit from Raffles Institution, 17, asked Dr Janil if the racial categorisation system - CMIO (Chinese, Malay, Indian and Others) - needs to be updated, given Singapore's increasing racial diversity.

Dr Janil said it was never a perfect marker, not even when it was first introduced. He said that the categorisation was there to allow other policies to be supported - such as Singapore's ethnic integration policy and mother tongue policy. "It is an enabler of all these things," he added.

The seminar began yesterday and ends on Thursday.