Couples could be asked a series of personal questions as part of the Government's move to axe child benefit for high earners.
The coalition's decision to means-test entitlement might lead to intrusive inquiries from tax officials as they tackle recipients they believe over-claim.%VIRTUAL-SkimlinksPromo%
Parents may have to declare their family circumstances alongside their earnings to determine whether they can claim the benefit, worth £20.30 a week for the first child and £13.40 for each subsequent child.
The benefit will be paid to couples unless they have opted out of receiving the money, though households where one parent earns more than £60,000 will have to return the entire amount through the self-assessment system.
The benefit will be reduced on a sliding scale for households where mothers or fathers earn between £50,000 and £60,000.
Families could be quizzed on the volatility of their relationship, who pays household bills and who funds children's pocket money, if anomalies are identified when self-assessment forms are returned, the Sunday Times reported.
But HM Revenue and Customs (HMRC) stressed households completing the forms honestly and accurately would not face questions.
A spokesman said: "HMRC believes the majority of its customers want to comply and we will be putting our efforts, in the first instance, into supporting them to do so.
"However, for those who choose not to play by the rules, we will use our standard compliance risk-based approach to tackling non-compliance, where appropriate.
"Nobody affected by the new charge needs to complete a tax return until January 2014, so HMRC will only contact people after that date, if further information is required. Nobody should worry about a call from HMRC where they have correctly told us about their circumstances."
Tax tricks to improve your wealth
Couples face child benefit grilling
If you wear a uniform of any kind to work and have to wash, repair or replace it yourself, you may be able to reclaim tax paid over the last four years. For some people, this could mean a windfall worth hundreds of pounds
The interest you receive on savings accounts (with the exception of cash Isas) is automatically taxed at a rate of 20%.
Higher-rate taxpayers therefore tend to owe money on the interest they are paid throughout the year. If, however, you are on a low income or not earning at all, you should be able to claim all or some of the tax deducted back
You can apply for a refund of vehicle tax if you are the current registered keeper or were the last registered keeper of your vehicle that no longer needs a tax disc
If you pay tax on a company, personal or State Pension through PAYE (the system employers use to deduct tax from your wages), you may well end up overpaying
There is a limit to the amount you need to pay in NI, whether or not you work for an employer.
Instances in which you may find that you have overpaid include if you work two or more jobs and earn more than £817 a week and if you move from self-employment to employment, but continue to pay Class 2 National Insurance contributions