“I think it’s very important for Singaporeans to be able to choose their own leader,” he said.
“That means we need to be confident that our democracy is being protected, that our country is not being taken advantage of.”
The country of 1.2 billion people has struggled to find a leader since Lee Kuan Yew’s departure from office in 1997.
Singapore’s leader, Lee Hsien Loong, was succeeded by the outgoing prime minister, Prayuth Chan-ocha.
More recently, a young candidate, Mr Lee Hui, took office in September.
He was narrowly beaten by Mr Lee Kwan Yew, who was prime minister from 1997 to 2003.
“We have to be very clear about what is going on,” Mr Lee said.
“If we do not understand the issues that are happening in our country, then we can be completely blind to them.”
In 2016, a report by the independent Commonwealth Electoral Commission found that Singapore had the third-highest percentage of non-white voters in the country.