HANOI • Vietnam's capital yesterday extended Covid-19 restrictions for a further two weeks, as the Hanoi authorities launched a plan to test up to 1.5 million people for the coronavirus in higher-risk areas to contain a climb in infections.

The South-east Asian country dealt successfully with the virus for much of the pandemic, but the virulent Delta variant has proved more challenging in recent months.

Hanoi, which has ordered people to stay at home and has halted all non-essential activities since July, has now divided the city into "red", "orange" and "green" zones based on infection risk.

"Accordingly, people in red areas must shelter in place and one person of every household there will be tested three times per week," a statement from city authorities said, adding that in other zones people would be tested every five to seven days.

Barricades yesterday separated red zones from other areas, photographs posted on social media and media outlets showed.

Hanoi expects up to 1.5 million test samples to be collected in the next week.

The government is eager to keep the outbreak from reaching the intensity seen in Ho Chi Minh City.

In the southern business hub, people have been encouraged to test themselves using antigen Covid-19 kits after health services were overwhelmed.

Hanoi has been reporting on average 50 cases daily and has posted over 4,000 cases since the pandemic began, official data showed.

Although the numbers are still low, officials are wary after the Delta variant drove up cases across the country to over 524,000.

One-third of Hanoi's 8 million residents have been given at least one dose of a vaccine and on Sunday the health ministry called on the capital and Ho Chi Minh City to vaccinate all adult residents with at least one dose by Sept 15.

Vietnam has one of the lowest coronavirus vaccination rates in the region, with only 3.3 per cent of its 98 million people fully vaccinated, and 15.4 per cent with one shot.

REUTERS