A man weighing more than 200 kilograms has died in hospital, after staff could not give him life saving treatment because he was too heavy for them to roll.

The man, believed to have been in his early 20s, collapsed from cardiac arrest at Middlemore Hospital.

Staff could not get him over onto his back to perform CPR, and he died.

The hospital's chief medical officer Don Mackie says average weight is increasing worldwide and hospital technology has reflected that.

He says this includes larger and stronger beds and wheelchairs as well as hoists to move patients.