"Singapore is concerned about the deteriorating relationship between Thailand and Cambodia. It is not good for ASEAN," said a spokesman for Singapore's Foreign Affairs Ministry.
"We hope that both our friends will keep the larger interest of ASEAN in mind and find a way to resolve their differences quickly in a spirit of good neighbourliness."
Thailand on Friday threatened to close its border with Cambodia in a spiralling diplomatic row over Phnom Penh's naming of fugitive former Thai premier Thaksin Shinawatra as an economic adviser.
The warning came a day after the two countries recalled their respective ambassadors due to the dispute over the appointment of Thaksin, who was ousted in a 2006 coup and lives abroad to avoid a jail term for corruption.
Cambodia, Singapore and Thailand are members of ASEAN along with Brunei, Indonesia, Laos, Malaysia, Myanmar, the Philippines and Vietnam.