The service, which is run by the NSPCC and Children England and had been funded by the government since 2009, is set to be stripped back to offer only a minimal online and local service to community and voluntary groups unless other funding streams can be found.
John Brownlow, head of professional engagement at the NSPCC, said the decision by the DfE to remove its funding from April 2015 was “extremely disappointing”.
He said: “It’s a unique resource for the voluntary sector which is feeling the economic squeeze and relies heavily on us for support.
"Although we will do our best to keep the website going it means we won’t be able to update it so much or invest in new materials which could result in more children being put at risk of harm. We will also have to cut back our local work with voluntary sector and community organisations.
“We need around £500,000 a year, which is not a large sum when you consider how many children we are helping. This is a severe blow particularly at a time when child abuse is constantly in the headlines and remains a constant concern for the public.”
Kathy Evans, chief executive of Children England, said: "Just like the airline industry's single collective safety framework, the third sector has collaborated nationally and locally over many years to create an effective shared child safety framework for all charity, community and volunteer work.
"DfE's investment in Safe Network succeeded in creating reliable accessible standards, tools and expertise, free at point of use for the whole sector. Its future was never entirely dependent on DfE funding, but their complete withdrawal of support at a time when Safe Network's demand has never been higher is premature, and frankly nonsensical."
Last year Safe Network - which provides safeguarding information related to activities outside the home, from after-school art clubs to weekend reading groups - attracted 750,000 visitors to its website and has 25,000 charities and community groups on its register.
Local safeguarding children boards also rely on its support, with a quarter using Safe Network standards for community safeguarding in their area.
Set up originally through the previous Labour government’s Staying Safe Action Plan funding, it also offers support to parenting groups on keeping children safe as well as specific help for charities in checking criminal records of staff.
A DfE spokesman confirmed that its funding for Safe Network would not continue when the current contract runs out at the end of March. In addition, Safe Network has been turned down for DfE voluntary and community sector (VCS) funding.
He said: “Applications for the VCS grants were highly competitive and, due to the high number and standard of applicants, not all bids have been successful.
“We will publish a full list of all the successful organisations later this month. This will include the amount of funding each organisation will receive and what we expect them to deliver for the funds.”