Due to technical problems, the Tax and Customs Administration gives people a week longer to file their tax return.
The submission period now runs until May 8 instead of May 1, a spokesperson told NU.nl.
The deadline to be notified before 1 July is also shifted by one week.
Anyone who wants to hear before that date whether he or she will receive a refund or whether they have to pay, must now file a declaration before 8 April.
That was April 1.
The Tax and Customs Administration has been struggling with technical problems since Monday, which means that not everyone is able to log in to My Tax Authorities.
The malfunction was not completely resolved on Thursday afternoon.
"We are cautious, but hope that we can quickly say with certainty that the problems are completely over," said a spokesman.
The Tax and Customs Administration asks people who try in vain to file a tax return to try again at a later time.
The tax authorities also point out the possibility of using the Tax return 2020 app, although it is not possible to file a tax return via the app in all situations.
The cause of the malfunction is still unknown
Due to the problems, the tax authorities limited the number of people who can file a tax return at the same time on Wednesday.
Still, the outage is not related to overload, the spokesman said on Tuesday.
"We can imagine that people are disappointed. And the Tax Authorities also find this very annoying," said the spokesperson.
"We apologize for the inconvenience and thank people for their patience."
The exact cause of the malfunction is still unknown, he continues.
"We are going to find out thoroughly."