Many hospital emergency departments are caring for patients in units where they can "stop the clock" on the Government's six-hour target.
District health boards are striving to comply with the target that 95 per cent of ED patients are admitted to a ward, transferred or discharged within six hours.
Compliance sits at 92 per cent in the latest national statistics, up from 80 per cent when the target was introduced in mid-2009.
Larger hospitals have created short-stay units of about eight to 10 beds in their ED which, for example, are used to observe drug overdose patients until they are well enough to go home.
Some hospitals have also created assessment and diagnostic units beside their ED mainly to take stable patients referred by a GP who may start treatment before having surgery, going to a ward or being discharged home.
Patients moving from an ED to either of these kinds of units are considered to have been admitted, so the six-hour clock stops - and doesn't start for those who go directly into an assessment and diagnostic unit.
"Short-stay units were kicking off pre-target," said Health Ministry ED chief Professor Mike Ardagh, "but since the target there has been a lot of work in them and how EDs have been working."
He said many people claimed they were built "just to stop the clock," but that was not the case, although he accepted it could appear so.
"It may seem DHBs are looking to these because of the pressure of the target. I think they are good - primarily we are doing them for [medically justified] reasons unrelated to the target."
Dr Tim Parke, clinical head of adults emergency care at Auckland City Hospital, emphasises the need to guard against "gaming" - the manipulation of compliance which occurred in Britain for its four-hour target.
"Hand on heart I can say there is no intentional gaming," he said. "It requires constant vigilance and policing to avoid gaming. It's fair to say there would be a temptation, but because this target came from clinicians in response to a real problem there is a real desire to make it work."
Short-stay units were used in England to boost apparent target performance, he said, by "fabricating" patients as inpatients in a short-stay unit, when in fact they remained emergency department patients.
"One of the ways we monitor that is we measure the number of people who have been designated as short stays and ensure that that's kept to within 10 per cent of the total [ED volume], and then ensure that less than 10 per cent of them then go on to being admitted."
Separately, the so-called "inappropriate attendance" at free-of-charge EDs of people with conditions that could be treated by GPs is sometimes blamed for emergency room crowding and delays. This is partly what led to extra DHB funding being given to a network of after-hours accident and medical clinics in Auckland to reduce their fees.
Dr Parke said this had had virtually no impact on his ED because these patients were few in number and relatively easy and inexpensive to deal with.
Waikato Hospital, however, said around 45 "primary care" patients came to its ED each day during the last Christmas-New Year period, a time of record attendances. Some wanted new drug prescriptions. "With Easter coming up next weekend we're working with Midlands Health Network to get the message out to the public that they need to plan in advance with primary care appointments," said hospital chief Jan Adams.
* The target is for 95 per cent of ED patients to be admitted to a ward, transferred or discharged within six hours.
* Some larger hospitals have created short-stay units and some have also created assessment and diagnostic units beside their ED.
* Patients moved to either of these units are considered to have been admitted, so the six-hour clock stops.
* Compliance sits at 92 per cent in the latest national statistics, up from 80 per cent when the target was introduced in mid-2009.