Over 100,000 people logged on to the tax office website on Sunday to file their 2014 tax returns.

The ‘mass interest’ in the site led to tens of thousands of people being told to try again later, the tax office said.

This year everyone in the Netherlands – some 6.5 million people – are required to complete their tax return online via a personal page. The automatic filing system went live on March 1.

People with simple finances will find much of their tax return has been completed in advance by the tax office itself.

‘Some 60% is done in advance but you have to do the rest yourself,’ tax adviser Ruud Zuidgeest told website nu.nl. ‘Check the whole thing. Even if the tax office has filled in amounts, you are responsible in the end.’

Tax returns have to be submitted by May 1, one month later than usual.