A volunteer sits on a chair to keep guard near barricades blocking a residential area in Wuhan. AP

The world should learn from China on combating the coronavirus - including considering a lockdown on cities - as the country saw a decline in daily increase of news cases, said the World Health Organization-China Joint Mission after its team visited ground zero.

Bruce Aylward, the leader of the team, said the approaches made by China have effectively "prevented hundreds of thousands cases" in the mainland and is an "extraordinary achievement."

He said China chose to lock down cities which had more than 15 million people, which has caused the decline in case increases.

Other countries are now the second line of defense and they should seriously consider applying similar measures before the virus gets into low-income countries that have weaker capacity to deal with it, Aylward said.

Liang Wannian of the mainland's National Health Commission said the lockdown of Wuhan since January 23 has help prevented the epidemic from spreading.

The commission reported 409 new coronavirus cases yesterday, down 239 when compared to 648 a day earlier, while more than 20 provincial-level jurisdictions including Beijing and Shanghai reported zero infection.

However, more than 3,000 medical staff in China had been infected, Liang said, citing a lack of protective gear and fatigue.

China should not gloat and should continue their effort on preventing the spread as the number may increase as work when classes resume, despite a downward trend observed, Aylway added at the briefing.

He suggested those countries that have imposed travel restrictions on Chinese visitors should reconsider their decision. The team of 20 experts has visited cities including Wuhan earlier this week.

Liang said the fatality number of the virus is now 3 to 4 percent nationwide and would be 0.7 percent if it excluded Wuhan. The briefing came after the Wuhan government reversed a decision to allow healthy non-locals and people having special reasons to leave the city - a partial lift of the lockdown implemented a month ago to control the spreading of the deadly coronavirus.

In making a U-turn, the authority said the announcement has not been approved by local leadership.

Initially, it was said that healthy people who meet specific requirements, including non-locals and those who need to leave the city to treat special illness or participate in operation of other cities, must apply and seek approval from the Wuhan authority before they can leave.

Less than three hours later, the command department said in a statement that the previous announcement, which was made by a traffic prevention group under the department, did not have the consent of "major leaders."

"The announcement is now declared invalid," it said, adding that the department had seriously dealt with responsible personnel.

Hundreds of foreigners have been evacuated from Wuhan by airplanes to their own countries, but around 2,700 people from Hong Kong have been stuck in Hubei province since the lockdown on January 23.