A doctor in the Chinese city of Wuhan said that thousands of patients are waiting for hours to see doctors.
BBC News declined to identify the doctor in order to protect her identity.
The new coronavirus can pass from human to human, and it has infected 830 people and killed 25 as of Friday morning.
As a precaution, the entire city of Wuhan, as well as other nearby cities of Huanggang and Ezhou have been locked down in an unprecedented quarantine against the disease, affecting about 23 million people.
The doctor told BBC News that scores of citizens have lined up at Wuhan hospitals in panic.
“The hospitals have been flooding with patients, there are thousands, I haven’t seen so many before,” the doctor said. “I am scared because this is a new virus and the figures are alarming.”
The doctor told the BBC that many people have to wait for hours before they can see a doctor, and little information is available to the public yet because of the novelty of the disease.
The doctor added that the typical incubation period of the virus is about seven days, meaning that many people can pass along the illness without showing symptoms.
“Screening is difficult because of the one-week incubation period — people may be travelling without realizing they have the virus. That means the actual figure of people infected is probably higher,” the doctor said.
This is a major concern for doctors on the frontlines of fighting the disease.
“It is spread through human-to-human transmission and there are also medical-staff infections,” the doctor told the BBC.
“We were told two days ago not to go to work at the hospital, because of the risk of the virus spreading,” the doctor added.
The doctor is not alone in concerns that the actual toll of the disease is higher than what has been reported.
The quick-spreading virus has fueled concerns that the Chinese government may attempt to cover up the severity of the disease as it did in 2003 during the SARS outbreak, which resulted in 774 deaths across at least 30 countries.
As of Friday, there were 15 reported cases of medical staff being infected by the disease in Wuhan. But doctors told the South China Morning Post they believe the true figure is much higher.
Two sources with direct knowledge of the situation told SCMP doctors and nurses at medical centers and hospitals in Wuhan were being infected at a quicker rate than reported. One source said the outbreak among medical staff was due to a lack of information and protective gear.
“Many were not initially informed about the potential for people-to-person transmission and even now we don’t have enough protective gear, test kits, and other supplies,” one Wuhan doctor told SCMP.