Paying a promotions company £90,000 a year to send out a form which is freely available online is a "waste of public money", a parenting website has said.
Mumsnet has called on ministers to review HM Revenue and Customs' contract with Bounty, which hands out baby bags to new mothers on maternity wards containing free samples of products, promotional material and a copy of the child benefit form.
The firm is paid £90,000 a year to give out the form and claims that around 82% of child benefit payments are made as a result of the forms it hands out.
In a letter to Treasury minister David Gauke, Mumsnet said the Government should cancel its contract with the firm.
The firm came under scrutiny last year after an article in a leading medical journal suggested some parents were approached by Bounty representatives on post-natal wards.
Glasgow-based GP Margaret McCartney wrote that Bounty makes a profit by selling parents' details to other companies, and said the hours after giving birth are"hardly an optimal time" to obtain consent about giving out personal data.
A survey by Mumsnet around the same time found that 17% of mothers felt that Bounty reps had implied they would not be able to claim child benefit if they did not hand over their personal data, a spokeswoman for the website said.
Later that year the Department of Health ordered all hospitals to review their systems for allowing sales people on wards.
Mumsnet chief executive Justine Roberts said: "Our members simply do not see any justification for HMRC maintaining a contract that wastes public money.
"There are several more practical and much cheaper ways to distribute child benefit forms, which are freely available online, including having them given out when children's births are registered - a method which would reach 100% of parents.
"We at Mumsnet would happily host the online form free of charge, and we're sure many other sites would follow suit.
"As we're sure the Treasury is aware, the Cabinet Office advice is that such services should be 'digital by default'."
An online petition calling for the termination of the contract has been signed by 66,000 people.
Clare Goodrham, general manager of Bounty said: "Once again, we are the target of a malicious campaign by a direct commercial competitor which is accusing us of providing a service that helps all mums, especially those who need child benefit most.
"Unlike Mumsnet, Bounty doesn't view the essential distribution of child benefit forms as a 'dubious' service, which is why we are proud to help all mums across the country access child benefit just as we have been doing for more than 10 years.
"According to the HMRC, 82% of all UK child benefit is paid as a result of the forms handed out by Bounty. This amounts to a saving for the UK taxpayer and puts the form directly into the hands of UK parents.
"While we believe that digital is the way forward, we realise that there are many parents in the UK who do not have access to the internet and/or a printer so would therefore not be able to claim child benefit online. It is parents like these who not only need child benefit most, but who also rely on the vital health information, money-off vouchers and free products which can be found in Bounty packs."
HMRC said it did not wish to comment on the calls for it to terminate its contract with Bounty.