Dutch government websites were paralysed for several hours overnight after a mass cyberattack which targeted several ministerial sites, a spokesman said.
"The government's sites have been the target of a DDoS attack since last night around 8:00 pm (1800 GMT)," Robert Wester told AFP, referring to a denial of service attack in which hackers bombard sites with traffic in order to jam them.
Computer experts worked through the night to restore the sites which appeared to be back online by mid-morning Wednesday.
The Netherlands has been the target of several cyber attacks in recent weeks including administrative services and banks.
More than 10 million Dutch citizens were unable late last month to use their official online signature to pay bills and taxes because of a so-called distributed denial of service (DDos) attack.
The use of the national DigiD system is widespread in the Netherlands, where more than 10 million people out of a population of 17 million rely on it.
DigiD users' personal details were not under threat, the government said at the time.
Several Dutch banks including ING, ABN Amro and Rabobank as well as national carrier KLM were also hit by DDoS attacks in recent weeks, rendering websites and online banking services inaccessible for several hours at a time.