HMRC is urging first-time Self Assessment filers to take time out from Christmas shopping to register for its online services now.

Newcomers to Self Assessment in 2012/13 include parents with incomes above £50,000 who received Child Benefit payments from 7 January 2013. They have to pay a tax charge based on their incomes and how much of the benefit they received in the 2012/13 tax year.

For those who have not signed up for online services before, registration can take up to seven working days to complete, as the final step involves HMRC sending taxpayers an activation code in the post.

HMRC is therefore issuing a warning that it is important not to leave this to the last minute, to avoid a rush to beat the 31 January filing deadline. Around 10.9m people are expected to fill out a Self Assessment return for the 2012/13 tax year.

There is general help and advice on completing a return via the link www.hmrc.gov.uk/sa. Alternatively, the Self Assessment helpline on 0300 200 3310 is open 8.00am to 8.00pm, Monday to Friday, and from 8.00am to 4.00pm on Saturdays.