http://www.ica.gov.sg/page.aspx?pageid=132#overseasbirth
An overseas-born minor (child) may be eligible for Singapore Citizenship by Descent under Article 122(1) of the Constitution of the Republic of Singapore, if his/her parents meet any of the following conditions:
Male Singapore citizen by Birth who has a lawful marriage at time of minor's birth
Male Singapore citizen by Registration who has a lawful marriage at time of minor's birth and minor does not acquire citizenship of the country he was born by reason of his birth in that country
Female Singapore citizen by Birth and minor born on or after 15 May 2004
Female Singapore citizen by Registration and minor born on or after 15 May 2004. Minor shall not acquire citizenship of the country he was born by reason of his birth in that country
Male (who has a lawful marriage at time of minor's birth) or Female Singapore citizen by Descent has to declare their residence period in Singapore. The application can only be accepted if the parent fulfils the requirements stipulated in the Annex.
The application has to be submitted within one year of the child's birth. Otherwise, a letter of explanation and additional documents are required for the late submission.
.
