Under new rules, child benefit will be means-tested for families where at least one parent earns more than £50,000 and will be cut altogether if a parent earns more than £60,000.

More than 365,000 people have so far opted out of Child Benefit since the changes were introduced in January.

Parents who continue to receive child benefit will need to register for self-assessment by 5 October 2013 to repay the benefit received between January and April 2013, but opting out now means they will not need to fill in a tax return in future years.

Anyone wanting to opt out of Child Benefit payments can do so by going to the HMRC website www.hmrc.gov.uk/childbenefitcharge

Parents who earn over £50,000 and who have received child benefit since 7 January 2013 will also need to register for self-assessment and complete a tax return for that period, regardless of whether they are now opting out.

Lin Homer, chief executive at HMRC, said:

“The decision to stay in or opt out of receiving child benefit payments is not final, and families are free to change their minds.”