Controversial draft guidelines on drugs for Alzheimer's disease have been revised, restricting some medicines.
Doctors fear the proposed guidelines will not help early diagnosis
Donepezil, rivastigmine and galantamine would be funded but only when new patients reach a moderate stage of the condition.
NHS advisory body the National Institute for Health and Clinical Excellence has made the new proposals.
Campaigners are angry that thousands of patients would not be entitled to the treatments in the early stages.
A fourth drug, memantine, which is used in the later stages of Alzheimer's, will not be funded for new patients - because NICE says there was not enough evidence of its clinical benefit.
Campaigners have been watching this process closely.
There was an outcry last March when NICE suggested that all four drugs should not be funded by the NHS because they were not cost-effective.
The manufacturers were asked to produce further data - and NICE has now changed its position after looking at the new evidence.
The institute's chief executive, Andrew Dillon, said: "By going the extra mile and asking the drug companies to delve deeper into their clinical trial data, we have been able to identify the right way to use these medicines."
But this does not go far enough for charities representing people with the disease.
Neil Hunt, from the Action on Alzheimer's Drugs alliance, said: "The new draft guidance still raises serious ethical and practical concerns.
"People with dementia and their carers value the benefits that the drug treatments bring in the early stages of the disease.
"For what other condition would you wait until people decline so much that they can no longer look after themselves before giving them treatment?"
NICE says that making the drugs available to people in the moderate stages of Alzheimer's will still benefit about 40% of those with the condition.
Their status will be determined by how they perform in a test called the Mini-Mental State Examination, or MMSE.
Doctors fear that the proposed guidelines could provide a disincentive for spotting the disease early.
Dr Duncan Forsyth, a consultant geriatrician at Addenbrooke's Hospital in Cambridge and vice-chair of the British Geriatrics Society's council, told the BBC News website: "The new GP contract is supposed to encourage doctors to diagnose dementia cases early on.
"But it's counter-intuitive to diagnose a condition if you can't then treat it. Also, this creates an inequity - it's not as if we're asked to score people before starting treatment for diseases like heart failure."
NICE is asking for views on these proposals during the next three weeks, and the drug companies are expected to make representations.
Although NICE guidelines cover England and Wales, the health bodies in Scotland often follow suit and Alzheimer Scotland said it would be monitoring developments.
A final decision will be made at a meeting in April, with the full guidance being published later in the year.