With classes resuming Tuesday after a monthlong winter vacation, local schools are on alert amid growing concerns over the new coronavirus.

Many children were seen wearing masks as they went to school or kindergarten, while some parents of preschool children said they plan to stay home with their children for the time being.

"I'm worried that some kids went to Ilsan or Pyeongtaek (during the Lunar New Year's holiday), where coronavirus patients were found to have visited," said a 36-year-old mother standing with her 5-year-old daughter at a kindergarten in Mapo in western Seoul.

"There's a lot of moms saying they won't send their kids to kindergarten for some time."

A 26-year-old mother who lives in Guri, south of Seoul, said she plans to stay at home with her preschool child.

"Contagious diseases spread very quickly at nurseries. I'm planning to stay at home with my child for a week," she said.

The sentiment was also strong online, where people shared information on the coronavirus or asked whether they should send their children to school or kindergarten.

"Would it be too excessive to ask my child's kindergarten teacher whether there are kids who visited China during the holidays?" one person asked.

"I was pregnant during the 2015 MERS crisis and had to wear a mask every day. Now that child has to wear a mask when going to nursery," wrote one mother.

Parents who both work seemed more concerned, left without the option of taking care of their children at home.

"I'm worried that a patient was roaming around Gangnam, which is not that far away. I don't even have anyone to take care of my child since my husband and I both work," said one mother who lives near the southern Seoul neighborhood.

Some parents demanded that education authorities extend the winter vacation.

Some 2,100 people have signed a petition asking the Seoul Metropolitan Office of Education to postpone the reopening of school, mostly scheduled for this week or next.

In a meeting with senior aides earlier in the day, Superintendent Cho Hee-yon said the office "needs to consider ways to manage students and teachers who have been to China," adding extending the winter vacation may be an option.

The Ministry of Education also held a meeting in which it decided to trace the movements of students, parents and teachers who recently visited the Chinese province of Hubei.

For those who have visited the area where the new coronavirus first emerged, the ministry plans to request them to self-isolate themselves for a minimum of 14 days upon their arrival here.

The ministry also distributed manuals to private-sector education institutions, urging them to closely monitor students and teachers.

As of Tuesday, four people in South Korea, including one Chinese and three Korean nationals, have tested positive for the new coronavirus that has killed more than 100 in China.

On Monday, President Moon Jae-in urged his staff to take "all possible measures" to prevent the disease from spreading, including a thorough check of all entrants from the Chinese city of Wuhan. (Yonhap)