Help is available to people struggling with their tax forms.
Personal tax returns have to be in by October 6th.
The Treasury is putting on additional help for people this week.
An out-of-hours telephone service will be in place at the following times:
Thursday - 5.30pm to 8pm
Friday - 5pm to 8pm
Saturday - 10am to 2pm
Business Solutions Group Manager Gerard Higgins says: "We have once again seen a marked increase in the number of people submitting their return online this year, and are ready to help more through the online process as the deadline gets closer.
"Staff will be on hand during normal working hours, but also into the evening on Thursday and Friday and on Saturday itself to enable people to take advantage of the process."
Those who don’t submit their tax form by the deadline will be fined £100.