The Southeast Asian nation announced a spike of 190 new infections over the weekend, mostly linked to a global Islamic event attended by almost 20,000 people.
“Of the 428 cases, 243 are participants from the religious event in Sri Petaling mosque,” Noor Hisham Abdullah, director-general of the health ministry, told AFP.
Authorities said participants at the gathering from February 27 to March 1 came from Bangladesh, Brunei, the Philippines, Singapore and Thailand.
Around 14,500 of the participants were Malaysian.
Brunei reported some 40 cases on Saturday, most in people who attended the Malaysia gathering.
Singapore has also announced cases linked to the event.
On Friday, Prime Minister Muhyiddin Yassin warned Malaysia of a second wave of infections spread and urged people to avoid mass gatherings.
Ahmad Farouk, a lecturer at Monash University, told AFP that authorities should shut down mosques for at least two weeks to contain the spread of the virus.