The workload for these heavy-duty ambulances has more than doubled in the past three years.

And specially designed air ambulances are also soon to be introduced.

NSW Ambulance was the first in Australia to introduce the ambulances, which cost nearly $100,000 more than a regular vehicle, in 1999.

Now two more multi-purpose vehicles (MPVs) have been added and the weight-carrying capacity of stretchers increased from 180kg to 220kg.

"The workload for these vehicles continues to increase — as does the range of tasks the vehicles are called on to perform," NSW Ambulance general manager of operations Michael Willis said.

Recent studies estimate 67 per cent of Australian men and 52 per cent of women aged 25 years and over are overweight or obese.

The weight epidemic has also extended to the school playground with NSW Health estimating that between 1985 to 1995 the number of children either overweight or obese has more than doubled.

The MPVs carry a specially designed stretcher and wheelchair and are also equipped with a hydraulic tailgate to enable patients to be loaded into the ambulance.

Mr Willis said the vehicles responded to emergency calls but were also used for routine transport such as hospital appointments and discharges.

"Due to their unique capabilities the ambulances also assist patients with routine medical appointments such as doctor or dentist visits, with examinations and treatment often completed in the rear of the MPV," he said.

When the heavy-duty vehicles are recruited to treat a big patient the service is usually required to call in a number of ambulances to assist with patient loading and movement.

"A recent case in Sydney’s northwest, where a 400kg man had fractured his leg at home, required the demolition of part of a wall and required multi-agency teamwork between ambulance officers and officers from NSW Fire Brigade and NSW Police," Mr Willis said.

"The case took 16 emergency services personnel five hours to complete."

The crisis has also forced an upgrade to air emergency services with new helicopters due to arrive in May which will have a greater load capabilities than the current fleet.

Via News.com.au