The outbreak began in November near the landlocked southern African nation's northern border with Tanzania and has since spread to other regions of the country.
UNICEF's representative to Malawi Johannes Wedenig told local media that "as long as people in Malawi don't change the behavior of using unsafe water, it'll be very difficult to contain".
He urged Malawians to follow strict sanitation rules and stressed the importance of hand-washing before eating or preparing food.
Cholera is a water-borne diarrhoeal disease that can kill within hours if left untreated, but is easily cured with oral rehydration, intravenous fluids and antibiotics.
Clean water and hygiene standards are critical to controlling transmission.
The country has also received 216,000 oral cholera treatment packs from the World Health Organization which are being distributed in the badly-affected northern region, health ministry spokesman Joshua Malango told AFP.
Another 450,000 doses are expected to arrive soon for distribution in the rest of the country, added Malango, confirming the current toll.
Health officials have begun a media blitz to educate people about the risk of cholera and what steps they can take to avoid contracting it.