Three Zika patients living in Bedok North Avenue 3 may constitute a new cluster of infection, indicating the spread of the virus beyond the Aljunied area.
Of the three individuals, who were diagnosed on Tuesday, one works in the Aljunied Crescent and Sims Drive area, where the first locally transmitted instances of Zika were diagnosed.
Two others have no known links to the area, the Ministry of Health (MOH) said in a press briefing yesterday.
The news has rattled Bedok residents like Ms Ng Hui Wei.
"I'm definitely worried. My sister just got married. She lives nearby in Jalan Tenaga and comes home to visit," said Ms Ng, 30, late last night.
MOH also confirmed two new cases in areas previously not known to be affected. One is a resident in Joo Seng Road, a stone's throw from Kallang Way, while another lives in Punggol Way.
Minister for Health Gan Kim Yong warned that more cases will come from other parts of the island.
"Over time, we expect Zika cases to emerge from more areas. We must work and plan on the basis that there is Zika transmission in other parts of Singapore," he said in a joint statement from MOH and the National Environment Agency (NEA) last night.
Operations to control the breeding of mosquitoes will be extended beyond the current areas. NEA will start vector control operations in Bedok North Avenue 3, where there are more than 6,000 premises to be inspected.
Officers from the agency may have to enter homes by force if home owners do not respond to notices, NEA said.
Singapore's first locally transmitted case of Zika - a woman living and working in Aljunied - was reported last Saturday.
By Sunday, testing of people with Zika-like symptoms in the Aljunied Crescent and Sims Drive area had uncovered 40 more cases, with 37 cases concentrated in a Sims Drive construction site.
These included retrospective cases, with one person in this group falling sick a month ago.
The number of cases jumped to 82 on Tuesday, and had spread to the contiguous areas of Paya Lebar Way and Kallang Way.
The authorities are also monitoring other areas where those who have fallen sick live or work.
But no cases have been found in these locations, which include Khatib Camp, Sembawang Drive, Joo Chiat Place, Toh Guan Road East and Lorong 101 Changi.
Bedok North was mentioned as a possible cluster for the first time yesterday, as MOH announced that a pregnant woman was among 24 new confirmed cases. There are now a total of 115 known cases of Zika here.
Nanyang Polytechnic student Syafiyatul Fatin Sudirman, 17, who lives in Bedok North Street 2 with her family, said she would start taking precautions.
"I'm a bit scared. It's a virus after all. My grandmother has plants at home and I always ask her to clear the pot trays. I think people should all do that more. Maybe I should start putting on repellent when I go out too. I'll ask my family to do the same."