Myanmar has a formidable task of nation-building ahead, but Singapore wishes it well and will lend a hand, Prime Minister Lee Hsien Loong said yesterday.

"We have been friends of Myanmar for a long time including during the difficult period over the last 15, 20 years when Myanmar was going on this very difficult road of reform and path to democracy... We hope we are able to make a contribution and help in Myanmar's development and progress," he said at the end of his visit to the country.

But as Myanmar develops and focuses on nation-building, Singapore hopes it will contribute to Asean, he added in an interview with Singapore reporters that covered bilateral ties and areas of cooperation.

PM Lee's trip is the first made by a head of government after the landmark election in Myanmar last November that saw the country's civilian government swept to power.

He said Myanmar had fallen behind the rest of South-east Asia and needs to "catch up on lost time" by building up a team that can develop policies and unite the country.

Among the challenges Myanmar faces is having to integrate more than 130 different ethnic groups, some of which are geographically separated and still in armed conflict, Mr Lee said. "It is not just about getting them to use the same working language, but how to bring them together as one nation. I think that is preoccupying the government considerably."

Over the past three days, Mr Lee met top Myanmar leaders, including President Htin Kyaw and State Counsellor Aung San Suu Kyi. A key topic discussed was how both countries can cooperate more closely.

Visa-free travel between Singapore and Myanmar from Dec 1 was announced on Tuesday.

Mr Lee said Singapore's airport and port management firms are also interested as the country opens up.

Singapore also wants to work on a bilateral investment treaty, and update its avoidance of double taxation agreement with Myanmar.

But Mr Lee said it is understandable that Myanmar wants to work out its own investment laws first. He said a stable financial environment and rules are important for development and encouraged Myanmar to create these conditions.

He also hoped Myanmar would play a role in Asean, saying it will be helpful as the grouping is often included in major talks on world issues such as trade and regional security.

"Through Asean, each of us, small countries in South-east Asia, can have a voice in world affairs... Myanmar has a role within Asean to play and we hope we'll be able to help them," he said.