An explosion occurred Wednesday near a COVID-19 test centre in the Netherlands, shattering windows but causing no apparent injuries, police said.

"Near the local health service's testing centre in Bovenkarspel, an explosive went off at 6:55 am. Police are investigating. The perimeter has been sealed off," the police said in a statement.

A bomb squad was sent to determine whether any explosive material remained at the scene, public television network NOS reported.

In January a Covid testing centre was set on fire in the Dutch village of Urk as protests broke out over the start of an overnight curfew in the Netherlands introduced as part of measures intended to rein in the virus.

The Netherlands suffered several nights of rioting, the most violent the country has seen in decades.