The number of positive coronavirus tests registered with public health institute RIVM rose 64% over the past seven days to 15,526.

The rise in official positive tests is probably connected to two new Omicron variants which are ‘gaining ground’ in the Netherlands, the RIVM said.

The RIVM is monitoring the spread of the virus via traces in waste water, and that total is also rising steadily, the agency said. More positive home tests are also being reported to website Infectieradar.nl.

Since March, people who have a positive test are no longer required to have it confirmed by their regional health board but the number of people requesting PCR tests is also going up. Regional health boards carried out over 18,000 tests in the week to Tuesday morning, the highest figure in two months.

Formal testing is primarily aimed at healthcare workers and people who have not been vaccinated and need a negative test result to travel. Two in three people having a formal test are also proving positive for the virus.

Hospital admissions are also rising but only slightly, the RIVM said.

The RIVM urged people who have symptoms to always do a test. ‘There are few flu cases at the moment, so cold-like symptoms could easily be a coronavirus infection,’ the agency said.

The health ministry this week outlined its long-term strategy for managing the virus, which focuses on avoiding lockdowns by creating sector-specific plans for education, catering, travel and other parts of society where the risk of infection is high.