The shared experiences of living in Housing Board towns and going through national service have made Singaporeans more united now compared with 50 years ago, said Prime Minister Lee Hsien Loong.
But external forces that could exploit enduring fault lines like race, language and religion and pull Singaporeans in different directions have also grown stronger, he warned.
PM Lee yesterday stressed the need to build bridges between different groups in society to counteract such divisive forces.
Such efforts have to go beyond bridging race, language and religion, he said, calling for social cohesion to be strengthened between management and unions, and old citizens and new.
He noted that the ethnic, cultural and economic pulls of regional powers like China and India will continue to exert a force on Singaporeans.
On one hand, Singapore wants to maintain its separate identity as an independent, sovereign and multiracial country, said PM Lee. But its relationship with China and India is complicated by ethnic links, cultural ties and its inside track to both nations.
"Between the two, there is tension, and we have to keep that balance and maintain our position and our cohesion," he said.
The situation is similar for Malay Singaporeans, he added. Despite the clear emergence of a Malay Singaporean identity, it still overlaps with the Malays in Malaysia, both in terms of race and religion.
The call for a global Islamic ummah, or community, also has a "powerful appeal", he noted.
Furthermore, Singapore is exposed to extremist and exclusivist teachings. In the event of a terrorist attack, it will sow great fear and distrust between Muslims and other Singaporeans, he said.
As for ties between other groups, he noted that in the new economy, there are fewer workers doing rank-and-file jobs traditionally covered by trade unions, with more workers becoming freelancers and professionals. If these new groups are left out, more workers will feel that their needs are not taken care of and look for other solutions, warned PM Lee.
"It would weaken tripartism and our social compact," he said, noting that this three-way partnership is a vital element of Singapore's social cohesion. It is thus better for the labour movement to embrace them and adopt their concerns, he added.
Singapore also has to build a bridge between old citizens and new ones, he said, adding that it needs a steady flow of immigrants to top up its population.
He also said new immigrants have to make every effort to mix with everyone else, but noted they will always take time to settle in - as previous waves of first-generation Singaporeans did.
"On our part, we should welcome them, we should support them in their journey to become Singaporeans, as others have helped our forefathers and helped ourselves."