SINGAPORE - Recounting Singapore's 50-year journey since independence, Prime Minister Lee Hsien Loong said that three factors were crucial in getting Singapore "from third world to first".

"Firstly, we determined to be a multi-racial society; secondly, we created a culture of self-reliance and also mutual support; and thirdly, we kept faith between the Government and the people," PM Lee said at the National Day Rally on Sunday.

The fundamental reason for Singapore's existence is its belief in multi-racialism, he said.

"We separated from Malaysia because we believed in this ideal of a multi-racial society," said Mr Lee.

Singapore moved towards this ideal by clamping down on chauvinists and racial extremists, Mr Lee said.

The Government made English Singapore's working language, and implemented housing policies to ensure that different races live together.

But while the Government encouraged all communities to come together, each community was given the space to maintain their own cultures and ways of life, he said.

When delicate, difficult issues arose, Singapore did not divide along racial lines, but dealt with the issues together.

When a Jemaah Islamiyah group was found to be planning to suicide bomb attacks in Singapore after the Sept 11 attacks, "we handled it as one people", he said.

He noted that at one SG50 dinner, he had representatives of all the world's major religions sitting at his table: "Each had different dietary rules, each was served food that met his religious requirements, but nothing stopped them from having a meal together and being friends together.

"In fact, they took a selfie together, which I posted on Facebook. Only in Singapore!"

But he cautioned race and religion remained sensitive matters. They are, in some ways, more complex and difficult to handle today than 20 years ago, due to the spread of extremist ideology, he said.

Religiosity has gone up and developed countries like US, Britain, Australia and Germany are seeing racial and religious tensions.

"We are a multi-racial and multi-religious society, we are always at risk of deep fault lines opening up," he said. "We must never take our present happy state of affairs for granted."

Another factor that contributed to Singapore's success is its culture of self-reliance and mutual support.

"We knew from the start that to strike out and blaze a path on our own. Everyone had to pull their weight and be counted. We couldn't afford free-riders," he said.

That was why Mr Lee Kuan Yew exhorted Singaporeans over and over again to become a rugged society.

But a rugged society doesn't mean every man for himself, and those who do well are expected to help others. "And everyone has to work together so that we succeed as Team Singapore," he said.

The third factor for success, the trust between the Government and Singaporeans, has allowed the country to "act decisively", even in tough times, PM Lee said.

"The Government has kept its promises. What we said we would do, we did do. We have kept our politics honest. We insisted on high standards of integrity in public life," he said.

The Government has also been honest about policies and the choices that Singapore has to make, he added.

"We don't shy away from hard realities, we do not sugar-coat difficult issues."

In Singapore's early years of independence, the Government passed laws to acquire land for building flats and infrastructure without having to pay market prices, but it was tough for landowners and those who had to be resettled, he said.

He thanked them for their sacrifice, saying: "But if the Government had not done this, we could not have housed our population, and we could not have transformed Singapore."

During an outbreak of Sars in 2003, the Government also passed laws urgently to quarantine people at home, and Singaporeans co-operated.

Recently, when South Korea had an outbreak of Mers, it had problems quarantining people, he said.

He sought Singaporeans' support to deal with new tough issues ahead.

"One tough issue which we already have, and will be with us for a long time to come, is immigration and foreigners," he said.

The Government has adjusted its policies to slow down inflows of foreign workers, tightened eligibility requirements for permanent residency and Singapore citizenship, and made sure that Singaporeans are fairly treated at work, he said.

Listing the trade-offs that have to be made in adjusting the flow of foreign workers, he said: "It is my responsibility to take this decision, and act on your behalf, and having done that, I will account to you for my actions."

The three principles - multi-racialism, self-reliance and mutual support, and keeping faith between government and people - have made Singapore special, and Singapore has to stay special, he said.

"Because if we are just a dull little spot on the map, a smudge, we are going to count for nothing. We have to be a shining red dot."