The return of the Charities Bill to the House of Commons is sparking concern for independent schools and private hospitals in particular.
And, according to Stephen Claus, a charity expert at Birmingham and London law firm Martineau Johnson, it could threaten the existence of some.
Mr Claus said: "The reap-pearance of the Charities Bill obviously brings with it a number of benefits, including the overall modernisation and improvement of charity law.
"However, the proposed changes could see some charities being denied their charitable status as a result of new complex obligations for organisations to prove that they are established for the public benefit."
The Charities Bill has been on the shelf for seven months but has now reap-peared and reached the scrutiny stage, having received its second reading debate at the Commons on June 26.
There is currently a legal presumption that a charity which either relieves poverty or advances religion or education is benefiting the public unless there is any evidence to the contrary.
However, under the Bill, this presumption would be removed, a factor that Mr Claus believes is rightly raising concern, particularly amongst those charities that charge some kind of fee for their service.
He said: "There are strong feelings that the Government's reintroduction of the Charities Bill will be accompanied by a controversial change to the 'public benefit' issue and I believe that this will impact negatively on the likes of private or independent schools and private hospitals.
"These types of organisations currently receive tax breaks as registered charities which may, under new rules be brought into question but if lost would be a huge drawback.
"Independent schools for example have already hit back, arguing that for every £1 they receive in tax breaks, they contribute £3 towards scholarships or bursaries."
A removal of the presumption of public benefit would see charities having to provide solid evidence of a positive effect instead, which could lead to mounting levels of paperwork.
Mr Claus said: "Even charities that are successful in proving their validity in respect of public benefit are likely to suffer at the hands of changing rules as they will also be subject to the new procedures and the demands these could make on their time."
The Bill will be subject to a series of discussions in July. Once it has passed through this stage it will be subject to further amendments, before heading for a third reading which will decide its final outcome.
"Whilst many MPs are looking for a stricter test to be imposed on organisations looking to obtain charitable status, I hope that the continuation of many existing organisations is also held in the same importance," said Mr Claus.
"Changes to the Charities Bill could be a real threat to many organisations which, despite charging fees or obtaining benefits as a result of their status, provide a valuable service for the benefit of the public and would be sorely missed."