The Public Health Ministry on Wednesday reported 35 new cases of coronavirus disease (Covid-19), raising the number of local infections to 212, and warned that lack of personal discipline could make the outbreak uncontrollable.

Dr Suwannachai Watanayingcharoenchai, director-general of the Disease Control Department, divided the new cases into two groups.

The first one of 29 was people in contact with previous patients and the venues where previous patients visited - 13 visitors to boxing stadiums, four visitors to entertainment places and 12 people in close contact with previous patients.

The second group of six was one Thai returnee from Cambodia, four people working closely with foreigners and one whose case was under investigation.

"In the past week, the number of patients soared because screening was expanded to groups of people and places believed to transmit the disease," Dr Suwannachai said.

"This goes along with the disease investigation, which showed that new patients exhibited risky behaviour and did not comply with advice from the Public Health Ministry. They continued to visit risk areas and crowded places, partied, and failed to reduce social activities, to keep their distance from others and quarantine themselves."

Those ill people transmitted the disease to family members and friends, and infected children and elderly people, and those with chronic illnesses suffered severe symptoms, he said.

He asked visitors to Lumpini and Ratchadamnoen boxing stadiums from March 6 to 8, and people who visited entertainment places and night restaurants on March 9 and 10 in Bangkok to monitor their own condition for 14 days, and see a doctor if they had a cough, sore throat, runny nose or breathing difficulty.