Although more than a million Danes have already peeked at their annual tax return at www.skat.dk, officials at tax authority Skat expect that today will still be a busy one online.

"We have prepared for additional traffic and increased our online capacity," Skat's head of IT, Jan Topp, told DR News.

Although about 1.1 million residents have stopped by the tax administration's website since last Friday afternoon, the weekend traffic was viewed as a mere warm-up for what is expected today.

"Traditionally, this is the day that many people log in, so we are doing everything possible to be ready," said Topp, adding that even though skat.dk is operating at "full speed" today, there could still be waiting times.

"If you can not get through, my advice is to try again later on, or maybe Tuesday or Wednesday," he said.

During daytime hours on Saturday and Sunday, between 1,200 and 1,700 users per minute attempted to access the website.  Many users vented their frustration on social media. One user posted a screenshot of Skat's website on Facebook which showed there were over 37,000 people waiting in the queue. 

The really bad news is that many may endure the endless wait only to find a tax bill waiting for them. Some 120,000 residents could face a tax hit due to changes is pension rules.

Last year, the rules were altered so that payments into an annuity of more than 50,000 kroner were no longer tax deductible.

Figures reveal that around 120,000 people have paid more than 100,000 kroner into their retirement savings funds.