The government announced earlier last month that GPs and other NHS workers would be banned from denying older patients treatment simply on the grounds of their age.
Michael Boyd, head of healthcare at business law firm DWF, said the new measures were being introduced because 'in too many instances, age has been a factor when deciding on a course of treatment'.
'Once this legislation comes into force, the onus will fall on healthcare professionals to make decisions that take the wider position of the patient fully into account,' he told GP.
'There will be a greater need for healthcare practitioners to be able to demonstrate that each treatment decision, in which age may have ostensibly played a part, was reached based on a broader consideration of the health and wellbeing of a patient - and not just their age.'
He said the rules would have a 'much broader impact' than simply affecting elderly care. 'The NHS should review all treatments in which age has been a determining factor in deciding whether they should be provided or not, and introduce practices which ensure that decisions are not made arbitrarily on the grounds of age.'
Code of conduct
David Gibson, a partner at DWF, said practices should review their codes of conduct so they can help to prevent GPs acting in a discriminatory way.
A NICE spokeswoman said the institute already took account of its legal responsibilities on all grounds of discrimination when developing its guidance.
'Recommendations in NICE guidance that make reference to a person's age are always based on the clinical evidence of what works best,' she said.
'In many cases, we make recommendations specifically in order to remove any chance of age discrimination.'
But RCGP chairwoman Dr Clare Gerada said older patients would often not be offered treatment because they would not benefit from it and doctors may simply be failing to explain decisions, rather than denying care.
'We shouldn't offer everyone the same treatment, regardless of their age,' she said. 'We need to accept that some old people will not benefit.'