Google has already updated its Chrome browser so it blocks access to any site which uses a DigiNotar certificate. Mozilla and Microsoft are expected to issue patches for their browsers soon. The Microsoft Security Response team tweeted earlier: "We're in the process of moving all DigiNotar CAs to the Untrusted Root Store which will deny access to any website using DigiNotar CAs."

This means hundreds of Dutch government sites will become inaccessible by browsers over the coming days if the agencies don't switch to another certificate issuer in time.

Last week, Dutch security company Fox-IT carried out a forensic examination of the cyber hack at DigiNotar. The preliminary results prompted the government in The Hague to go into crisis mode, putting in effect an immediate stop to any DigiNotar services, and taking over the operational management of the DigiNotar Certification Authority.

The report on this investigation will be send to the Parliament and made public on Monday.

DigiNotar did not respond to a request to comment on this story.