He was speaking after meeting visiting Indonesian President Joko Widodo.
Lee said the leaders regretted the lack of progress on a peace plan led by the Association of Southeast Asian Nations (ASEAN) on Myanmar, which has been gripped by violence and unrest since a coup in February 2021 that upended a decade of democratic reforms.
"Singapore will continue working with Indonesia and ASEAN members, plus ASEAN's partners like the U.N., to push for the full implementation of the five-point consensus," he said, referring to the peace plan that Myanmar's top general agreed to with ASEAN.
Indonesia currently chairs the 10-member ASEAN bloc.
In addition, Singapore and Indonesia would work together on developing renewable energy, their leaders announced.
The agreement was among several memorandums of understanding signed by the two countries, including Singapore sharing knowledge that could support the development of Indonesia's new capital Nusantara.