Foreigners can buy private condominiums, private executive condominiums more than 10 years old, landed properties in Sentosa Cove, or other landed properties if granted special permission by the Singapore Land Authority. If the property is restricted or has a residential component, you must obtain approval from the Controller of Residential Property at
http://www.sla.gov.sg before completing the purchase. If there are concerns about tax obligations when buying from a non-resident property trader, you can refer to
http://www.iras.gov.sg.