At least 3,214 samples were tested for COVID-19 in the last 24 hours, which put the single-day positivity rate at 6.31 per cent, he said.
Of the 203 fresh cases, Aizawl district reported the highest at 158, followed by Lunglei at 24 and Kolasib at 11, he said.
Siaha district reported three cases, Saitual four, Serchhip two and Mamit reported one case of the coronavirus.
More than 52 children and a healthcare worker were among the newly infected people, the official said.
Four patients have travel history, while 150 patients were diagnosed with COVID-19 during contact tracing and it is to ascertain how the remaining 49 patients contracted the infection, he said.
As many as 145 patients have developed symptoms of COVID-19 and the remaining 58 are asymptomatic, he said.
Mizoram now has 3,370 COVID-19 active cases, while 10,769 people have recovered from the infection.
The death toll in the state remains at 57.
The recovery rate is 75.86 per cent and the death rate is 0.41 per cent.
The state has tested 4,17,798 samples for COVID-19 till date.
According to state immunisation officer Dr. Lalzawmi, as many as 2,74,383 people have been administered the first dose of COVID-19 vaccine of which 52,535 have received both doses till Tuesday.