Ill-prepared families are dumping their elderly relatives at hospitals before setting off on their holidays in a practice known as ''granny dumping''.
Waikato Hospital clinical director Dr John Bonning said the problem increased at this time of year when some families wanted a stress-free holiday.
He believes it could worsen in the future, as the elderly population is forecast to increase markedly.
Advocates for the elderly said they were aware of the issue and thought it was getting worse.
Dr Bonning said anecdotal evidence showed elderly patients, most of them frail but without physical disabilities, were being abandoned at hospitals because families had not properly prepared for their care in their absence.
''You will get a small spike of it before a long weekend ... and before and around holidays, which indicates the family is trying to look after them during office hours but then have their lives to get on with,'' he said.
''It certainly is happening and there is a bit of that but I think we have got a bit of duty to look after our elderly population.''
Waitemata District Health Board spokesman Errol Kiong said ''granny dumping'' was ''apparently a phenomenon at every DHB around the country''.
Dr Bonning blamed a lack of planning, more than a shifting of care from families, for a problem that emergency staff were under-resourced to deal with.
But he said hospital staff had a duty of care to look after the elderly and could not turn them away, so many were staying for at least 16 hours in observation units.
With the elderly population set to rise, the issue would probably exacerbate, he said.
''I do want to suggest that people plan for these eventualities because we do find it very frustrating when people come in and you look at them and you think: 'Why wasn't this sorted out when it could have been so much simpler?','' he said.
''It's not in everyone's family relationship to be able to be at the beck and call of their elderly relatives, but if you're not going to do that, think of some alternatives when there's lots of infrastructure around - plan it, as opposed to being surprised at the last minute when the straw does break the camel's back.''
Care Association chief executive Martin Taylor said the issue had ''probably been increasing''.
A lack of short-term, readily available respite care for the elderly was also proving a hurdle for some families, who were turning to hospitals when they could not find an alternative.
''What we more frequently have is people ringing our office saying: 'How do I get respite care for Mum and Dad?','' he said.
''They could get to the situation where the lack of respite care means that they then think the best place we can go is the hospital.''
He said the daily rate that respite care facilities received for short-term patients was not good and their preference was to have long-term residents.
''What's been progressively happening throughout the country is facilities are saying :'I can't afford to keep two beds aside for respite care and I will only take respite care if I have an empty bed because I am waiting for a long-term resident'. The result of that is the supply of respite care beds or planned beds is minimal.''
He struggled with the notion that families could abandon their elderly over these periods.
''I know it happens, but it is very disappointing. It's not the way to treat the elderly.
''On the other side of it, if the health system isn't looking at the causes of that problem and seeing there is a way of addressing them, then that's equally poor.''
