In the past year, 18.8% had visited an emergency department, compared with 12.8% of the general population, and 32.8% had been dispensed 10 or more medications, compared with 14.2%.
The study also hinted at diagnostic inequity because Māori and Pasifika were under-represented.
"It is certainly not consistent with the general trends of benefit use in the population.
"So a low percent of Māori, low percent of Pasifika in this ME group on a benefit is very different to the distribution of ethnicity among that other benefit group.
"There is some evidence around access and equities of access to diagnosis."
Long-term data on employment, unemployment and benefit reliance showed how debilitating the condition was, he said.
Only 18.3% of people with ME/CFS were employed, compared with 83.8% of the general population.
Even when looking back one, two or five years, about half of those affected had earned no labour-market income in the preceding five years.