French schoolchildren above the age of 11 will be required to wear masks when they return to school in just over a week in a bid to halt the quickening spread of the coronavirus, the education minister said.

The new policy marks a toughening of measures as coronavirus infections pick up pace in France, with 4,700 new cases reported on Thursday -- a massive increase on the previous day and a post-lockdown record.

"Use of masks will be systematic inside from middle school and not only where there is no social distancing. But outdoors, it's a local decision," Education Minister Jean-Michel Blanquer said in a televised interview late Thursday.

The government will provide masks for families with limited income on a case by case basis, Blanquer said on Friday as he visited a school in the Oise region in northern France, an area heavily affected by the virus.  

The measure concerns pupils between the ages of 11 and 18. Pupils are due to return to school on September 1. Blanquer ruled out any nationwide delay to the start of the school year, a move advocated by some teachers' unions worried about the spike in infections.

New infections across France have been increasing in recent weeks and the numbers of people admitted to hospital and to intensive care have been rising as well.

Paediatricians on Wednesday called on the government to establish clear and precise strategies to deal with the discovery of a COVID-19 infection within a school. "We immediately test the class and the school, and from that moment we trace the chain of transmission," the minister said, responding to their concerns.

Blanquer said he was paying close attention to paediatricians' opinions and said he would be willing to extend obligatory mask-wearing to nine- and 10-year olds. Masks are compulsory in the busiest areas of many French towns and cities, including Paris and Lyon, on public transport and in all shared-work places.

After initially casting doubt on the value of masks as an infection barrier, the French government has recently been promoting their use. The coronavirus outbreak has claimed more than 30,400 lives in France so far.