There's no capacity in the community to provide the facilities needed for obese people leaving hospital.
The Counties Manukau District Health Board said the patients no longer required hospital treatment but still needed rehabilitation or recovery in the community.
However, their size meant it was difficult to find facilities which could accommodate them.
The longest stay was for a man with spinal injuries who had been at Middlemore for 248 days and who needed modifications to his home before he could return.
He had been turned down by 18 community residential care units until one recently said it could take him.
Otago University's deputy head of the medicine department Jeremy Krebs told Heather du Plessis-Allan their obesity makes the management of their condition that much more complex.
"When it comes top trying top discharge them back into the community, we're seeing these hold ups because these people are simply too unwell to go back to the places they've come from."
The DHB's chair Mark Gosche said the cases were a symptom of the severe pressure Middlemore is under from an obesity crisis.
There were 36,000 morbidly obese people in its community - more than double the number of any other DHB.
That made the area a special case and he was asking the Government to help with funding to help prevent obesity, Gosche said.
Health Minister David Clark said there was likely to be more preventative funding in the new Pacific Innovation fund announced in the Budget, and there may be other funding changes in an upcoming review.
- With content from RNZ