Customers who have already submitted paper returns do not need to do anything, however there will be a significant delay in the issuing of their assessment.

The filing of returns online is not affected by these issues, so the service said it would encourage customers, where possible, to submit their returns online.

Additional staff will be based at the Corporate Customer Counter (Level 3), Edward T Wheadon House for the duration of this week to provide support for customers to either submit their returns online or register for online services.

"We’re being hampered by a software issue that is taking a little while to resolve, but we know it’s important we make our customers aware of the problems this is causing. Those customers that have completed paper returns this year will experience a much longer delay in receiving their assessment, for which we apologise.," Sarah Davies, Head of Customer Service ah the Revenue Service said.

"We would very much appreciate if those of ourcustomers who haven’t sent in their returns could do so online as this is not affected. Customers that have already submitted a paper return have the option to resubmit online."

As the public lift is still out of action in Edward T Wheadon House, alternative arrangements have been put in place for any customers who are unable to use the stairs to ensure that they can continue to access the services.