I recently came across this initiative started by the Personal Data Protection Commission Singapore (PDPA) to curb this growing problem, the Do Not Call (DNC) Registry. It allows you to opt out of all sorts of marketing messages including those on your mobile, fixed line, residential or business numbers.
Organisations are prohibited to make any phone calls, send any text messages and fax messages to any number which is registered in the DNC registry. However, do note that the DNC only covers messages which are of commercial nature and does not cover messages for pure market survey, research, promotion of charitable or religious causes, public messages sent by government agencies or political messages.
Registration will only commence on 2 December 2013 and come into force on 2 January 2014 to allow time for organisations to review and adopt internal personal data protection policies and practices and comply with the PDPA.
Addendum: Now opened for registrations!