Singapore needs an opposition which understands the country's interests and does not seek to undermine them, Prime Minister Lee Hsien Loong said yesterday when giving the S. Rajaratnam Lecture on foreign affairs.

Such political unity is needed for domestic success. And domestic success - which means having economic prosperity, peace, a well-run state and strong defence - is what underpins successful foreign policy, Mr Lee said. "Singapore must continue to succeed as a nation to wield any influence at all."

He stressed that being united politically does not mean having no opposition. Rather, it means that Government and opposition "come together after elections, especially when dealing with other countries".

What is needed is "an opposition that will understand Singapore's fundamental interests in the world and will not seek to undermine them, to court foreign support or to gain political points", he said.

Singapore has had opposition politicians like that, he added, and cited former Member of Parliament Chiam See Tong.

"Whatever our domestic disagreements... when he travels overseas, he stands up for Singapore and closes ranks. And that is really the norm that should prevail in politics in Singapore."

Mr Lee noted that where "politics is fractious", foreign policy changes with the political winds.

This makes cooperation with other countries difficult, as partners cannot be sure that what is agreed with one government will be honoured by the next.

It also makes it easier for other countries to take advantage of the political uncertainty, by simply waiting for governments to change.

It is thus important for Singapore to maintain a clear foreign policy direction and pursue that in the long term, Mr Lee concluded.

Singaporeans must also be united "regardless of race, language and religion", he said, adding that the country's ethnic groups have cultural ties to corresponding groups in India, China and South-east Asia.

This is an asset as it aids cooperation, but also a vulnerability if "external ethnic or religious pulls split us along the primordial fault lines".

"So we have to keep working at our racial and religious harmony, and keep strengthening our shared Singaporean identity," he said.

Mr Lee noted that on the world stage, Singapore is careful to maintain a distinction between ethnicity and Singaporean identity.

When Singapore leaders meet Chinese leaders formally, they speak in English and use interpreters - even if they know Mandarin. "It's an important point of principle."

Mr Lee recalled once explaining the difference between "Singaporean Chinese" and "Chinese Chinese" to a Japanese prime minister - who then asked his interpreter what "Chinese Chinese" meant.

Not everyone might understand the difference, he said. "But the distinction is critical to us in a multiracial society."