The number of new coronavirus cases in the Netherlands has increased for the third week in a row, with 1,329 infections reported in the last seven days.

The latest weekly update by the public health agency RIVM shows there were 342 more new cases than in the third week of July, representing a 35% increase. A week ago the number of new infections almost doubled from 534 to 987.

The total number increased on Tuesday by 223, the highest daily figure since May 21, while the R0 number, which indicates how many people each infected person passes the virus on to, went up from 1.29 to 1.40.

Another 23 Covid-19 patients were admitted to hospital, four more than a week ago, and nine more deaths were recorded.

The RIVM said it was seeing more clusters of infections, with 133 identified clusters of between three and 30 people. The majority of cases where the source of the infection has been traced are in family groups.

Virologist Aura Timen, who described last week’s figures as a ‘wake-up call’, said the trend in the last seven days was ‘reassuring’. ‘We’ve still seen an increase this week, but it’s not going as quickly as last week,’ she said.

The government’s Outbreak Management Team met on Tuesday to discuss whether face masks should be made compulsory in more situations to curb the spread of the virus. There have been growing calls for tougher measures from areas with high infection rates, such as Rotterdam, where city mayor Ahmed Aboutaleb has also said the quarantine rules for travellers from high-risk areas should be more strongly enforced.

The most recent spate of infections is concentrated in the provinces of Noord-Holland and Zuid-Holland, which accounted for two-thirds of positive tests in the last two weeks, as well as Zeeland, which had more cases per head of population than any province apart from Zuid-Holland.

Much of the rise can be attributed to a rise in testing. A total of 111,764 tests for coronavirus were carried out in the week to July 26, an increase of 25.7%.

In the 41% of cases where the source of the infection could be traced, 85% caught the virus at home, on family visits or at work. Just over 8% of people who tested positive for the virus had travelled to foreign countries in the last two weeks, of which 46% had visited Belgium.