Singapore will support a new United Nations agreement to reduce mercury pollution and poisoning, Minister for the Environment and Water Resources Vivian Balakrishnan said on Friday.

He was giving a speech on behalf of Singapore in Kumamoto, Japan, where a diplomatic conference to adopt the agreement ends on Friday. The UN agreement sets out measures to reduce or ban the use of products with mercury, among other recommendations.

Singapore was among the first countries to sign the document, called the Minamata Convention on Mercury, when it was opened for signatures on Thursday. It will take effect when 50 countries sign and ratify it.

"Singapore is a dense city state with no natural hinterland... (so) our people are exquisitely sensitive to any environmental threat," said Dr Balakrishnan, adding that the Republic has already banned the import of clinical thermometers and batteries with mercury in them.