Facing citizen discontent over the growing number of non-Singaporean residents, Singapore's government is raising the barriers that control the inflow of foreigners.

Starting Sept. 1, foreign workers seeking to sponsor their spouses and children to accompany them while they live and work in Singapore will need a minimum monthly income of 4,000 Singapore dollars (US$3,150), up from the current S$2,800, the Ministry of Manpower said in a statement. The average wage of Singapore residents, including noncitizen permanent residents,...