By Nick Triggle
BBC News health reporter
A flagship NHS target could starve other areas of the health service of money, experts are warning.
From 2008, patients will be seen within 18 weeks, ministers say
Ministers have set the NHS a goal of ensuring every patient is treated within 18 weeks of GP referral by 2008.
But doctors and academics have voiced fears "Cinderella services" such as elderly care and maternity could suffer as hospitals strive to meet it.
The Department of Health said the NHS was receiving adequate levels of funding to hit the "ambitious" target.
The 18-week target is widely-acknowledged as the toughest that has been set since Labour came to power.
Both the A&E and GP wait targets have been largely met, but there is real doubt within the health service over whether this goal can be reached.
The then Health Secretary John Reid set the target after criticisms people were often waiting for months between GP referral and diagnosis, as other waiting time targets only kicked in after diagnosis.
A Liberal Democrat survey of 158 hospital trusts last year found patients were waiting for up to six months or more in two fifths of hospitals for routine MRI scans.
Richard Lewis, a fellow at health think-tank King's Fund, said it was such a hard target to meet, and so much funding might need to be channelled towards it that other areas could suffer.
At the moment, 43,200 patients are waiting longer than six months for treatment, but that does not include the wait for GP referral to diagnosis.
By the end of the year, the government has promised no-one will wait longer than six months.
Mr Lewis said: "The danger could be that it would require such an effort that other services would not get a look in."
The British Medical Association agreed services such as elderly care could be hit.
A spokeswoman said the danger was that managers would end up "pressurising their staff", while doctors were left to fight their corner to treat patients on a clinical need rather than tick-box basis.
Nigel Edwards, policy director at the NHS Confederation, which represents health service managers, said the target had the potential to benefit patients.
But he warned: "The reform agenda is so large there is a danger that by trying to do too many things at once, we lose sight of the end goal."
A Department of Health spokesman dismissed the fears.
"The new 18-week target is certainly a challenging one, but one which the NHS is more than capable of meeting.
"By 2008, funding for the NHS will be more than £92bn, an increase of more than £15bn over the next three years."