The centre received 15,684 calls from September 14 to 22, averaging more than 1,740 a day and up nearly 16 per cent from its previous daily average.
Calls reached 2,003 on September 19, exceeding 2,000 in a single day for the first time, the centre said.
Of the calls received during the nine-day period, 1,482 involved potential emergencies. The city's emergency medical network dispatched ambulances 1,242 times, or an average of 138 a day, nearly 10 per cent above the previous average.
Cases included unconsciousness, accidents, breathing difficulties, strokes, cardiac arrest, fire-related emergencies, multiple injuries, mental health emergencies, seizures and dizziness.
The centre said heavy rain and flooding raised the risk of traffic accidents due to slippery roads, flooding and poor visibility, as well as injuries from falling trees and signs. Other hazards included falls in flooded areas, drowning and electric shocks.
It warned that electrocution could occur both outdoors and inside flooded homes when water comes into contact with electrical sockets, wiring or appliances.
Residents were advised to slow down and maintain safe distances while driving, avoid deep or fast-flowing floodwater and stay away from large trees, electricity poles and billboards during heavy rain.
People in flooded homes should avoid electrical equipment or water where electricity leakage is suspected, while particular attention should be paid to children, older people and those with limited mobility.
The centre also urged people to ensure their own safety before helping others in flooded areas or places with electrical hazards or strong currents.
In an emergency, residents should call 115 promptly and provide accurate information about the location, the patient's condition and any hazards at the scene.
With call volumes remaining high, the centre urged residents to use the 115 hotline only for emergencies and keep calls brief and accurate to ensure lines remain available for those in urgent need.