The number of positive coronavirus tests increased on Wednesday for the seventh time in eight days to 6,589, the public health agency RIVM said.

The number is 34% higher than a week ago and reflects the underlying rising trend that began at the start of December.

The increase is partly due to testing capacity being expanded to allow anyone who has been in contact with an infected person to be tested, even if they do not have symptoms. However, the RIVM’s latest weekly bulletin showed the positive test rate has gone up to 11.6% and the reproductive number R is back up to 1.

Hospital admissions and intensive care numbers have also flatlined and the head of the national acute care network, Ernst Kuipers, said he expected the numbers to rise over the Christmas period. ‘That means a heavy workload for hospital staff over the holidays,’ he said.

Latest figures show there are currently 1,684 Covid patients in hospital, a drop of 16 in the past 24 hours, but the number in intensive care has gone up from 464 to 473.

Another 66 people were reported to have died, compared to an average of 48 a day over the past week.

The RIVM’s head of infectious disease control, Jaap van Dissel, warned on Wednesday that the number of people with the virus could treble by the beginning of January if people let their guard down over Christmas.

Scientists estimate that 88,000 people are currently infectious, but if the reproductive number R is sustained at its current level that number would rise to 117,000 in the New Year. If the R rises to 1.25 as people circulate during Christmas it would translate into 171,000 people and if it reaches 1.5 – the level at the start of the outbreak in March – the figure would increase to around 300,000.

Kuipers told the briefing that hospitals could be closed to visitors in the wake of reports of aggressive behaviour towards staff by patients’ friends and relatives. ‘We want to allow visitors during this second wave and not close hospitals, but if this carries on we may have to,’ he said.