The Home Office has been accused of burying a long-awaited consultation that could recommend that people who work with children should be forced to report concerns of child abuse.

Documents seen by the Observer confirm that an impact assessment, necessary for the consultation to begin, was signed off last October. But the consultation, which concludes next month, did not begin until 29 July, the last day of parliament, when it was published along with 30 written statements.

The impact assessment suggests that high-profile abuse cases such as those in Rotherham and Oxford have “exposed professional and organisational failings to respond to child abuse and neglect”, and that there is a case for considering action against professionals who fail to take “appropriate action in relation to suspected child abuse”.

Now the manner in which the consultation was launched has prompted claims that the government is dubious about the merits of mandatory reporting – a requirement for certain organisations and employees working with children to report child abuse or neglect if they knew or had reasonable grounds to suspect it was taking place. Currently there is no obligation for anyone in the UK working in a regulated activity to report the fact that they have witnessed abuse.

Supporters of mandatory reporting, which is observed in many other countries, say it would mean professionals could not turn a blind eye and would have to report their suspicions or face prosecution.

The government’s apparent lack of enthusiasm for the consultation is in marked contrast to its earlier position. A letter from the former Home Office minister Lord Bates, dated 23 November 2015, to Baroness Walmsley, the Lib Dem peer, confirmed that the consultation would begin “shortly after the New Year”.

Last year the then prime minister, David Cameron, outlined plans that would see teachers, councillors and social workers in England and Wales who failed to protect children jailed for up to five years.

Walmsley, who backs mandatory reporting, expressed frustration at the way the consultation was being handled. “I do think they’ve buried it,” she said. “It was ready months and months ago and they didn’t release it. I’ve been harassing them and hassling them ever since the consultation was promised, which was a very long time ago. Now it’s happening at a time when those who will be most affected by it – teachers – are on holiday.”

Walmsley said the government feared that the new law would result in system overload.

But evidence from an expert, Ben Mathews, a professor of law at Queensland University of Technology, which has been omitted from the consultation, suggests the measure significantly increases detection of abuse.

Tom Perry, founder of Mandate Now, which campaigns for mandatory reporting, was scathing about the government’s approach to the consultation. “The principal objective of the consultation is to keep the number of [abuse] referrals down in order to save money,” Perry said. “It has nothing to do with improving child protection.”

He said claims that “dinner ladies would be jailed” for failing to report signs of child abuse revealed the level of ignorance about the proposed new law.

“The government are being advised by the NSPCC and for some reason the NSPCC are not in favour of legislation about mandatory reporting,” Walmsley said. “They are mistakenly thinking it will affect social workers – which it won’t because they don’t work in a regulated activity. Those of us campaigning for this want it to affect only those in regulated activities – we’re talking about schools, hospitals, youth clubs, GP surgeries. We need to make sure people are obliged to report if they seriously suspect a child is being abused. People need not just the freedom to tell what is going on, but a duty and to feel that they are protected if they do that.”

Kath Stipala, head of public affairs at the National Association of People Abused in Childhood, said the organisation was “broadly in favour” of it. “The evidence we have seen from Ben Mathews comparing similar places with one another suggests we’d get better reporting and that it saves money in the long term. If you look at the comparison of Victoria and Ireland, carried out in 2010, the evidence is that mandatory reporting will detect much more child abuse and pick it up earlier.”

A Home Office spokeswoman said: “In line with our commitment as part of the Serious Crime Act, we launched a consultation in July on possible new measures relating to reporting and acting on child abuse and neglect. It’s important we get this right – which is why we are seeking views from practitioners and professionals as well as the wider public. We urge everyone with a view on these issues to respond and ensure their voices are heard.”