Mr Lee told reporters he emphasised two points.

First, that the large-scale iconic projects which the Singapore Government had agreed in principle to partner Malaysia on could not get off the ground without private investors.

Second, these private investors would not follow the Singapore Government's lead if they were worried that it would be 'cooperation this year and no cooperation next year, cooperation again year after that'.

The two iconic projects are the Iskandar Malaysia economic corridor and a third bridge between the two countries.

'The Singapore Government cannot do it alone, but investors will not follow us unless they are absolutely sure this is for a long, long time, not just chopping and changing,' Mr Lee said.

He was frank with Malaysian leaders, he said, and told them that Singapore businessmen now have thousands of projects in China, Vietnam, India and the Persian Gulf states.

They are also benefiting from the web of free trade agreements that Singapore has signed with large economies, including the United States, Japan, Australia and India.

If investors see no improvement in bilateral ties, they will keep their businesses where they are rather than take new risks in Malaysia, Mr Lee said.

Asked what the Malaysian government thought of his visit, Mr Lee said Singapore had kept the federal authorities informed of his itinerary. They provided police escorts all the way.

Read the full report in Tuesday's edition of the Straits Times

lydia@sph.com.sg