More than €1.3m was spent last year providing surgery to treat morbidly obese patients, according to new figures from the HSE.
A total of 154 patients went under the knife, a fall on the previous year when there were 169 procedures at a cost of €1.48m.
Figures from the HSE show there was €5.7m spent on obesity surgery over the past five years with a sharp rise in the number of cases being dealt with in recent years.
The number of patients who had procedures for obesity in public hospitals totalled 649 in the period between 2015, when there were 99 cases, and 2019, when there were 154.
Current guidance recommends surgery only if the patient meets certain criteria including having a Body Mass Index (BMI) of greater than 40, or a BMI of 35 to 40 if accompanied by a disease - such as type 2 diabetes - that weight loss would improve.
A body mass index of between 18.5 and 25 is generally considered healthy.
The HSE said appropriate non-surgical measures are tried first and "bariatric surgery" is considered when the person hasn't "achieved or maintained adequate, clinically beneficial weight loss".
They said patients will receive intensive management after their operation, and need to commit to the need for long-term follow-up of their progress.
The HSE also said Ireland has the fewest numbers of bariatric surgeries in the western world, performing less than 1 surgery per 100,000 people per year.
A spokeswoman said: "To be in line with international averages, Ireland needs to build up to performing close to 1,000 of these procedures each year."
She said the surgery was provided publicly in two hospital groups - Saolta (University Hospital Galway) and in Ireland East Hospital Group (St Colmcille's, St Vincent's and St Michael's).
The two procedures offered are sleeve gastrectomy - effectively reducing the size of the stomach to the size of a banana - and gastric bypass, dividing the stomach and changing the way the body handles food.
Covid-19 affected the provision of surgical procedures for complex obesity this year.
An information note said: "Ireland still lags behind other developed countries in the provision of this cost-saving, health-enhancing surgery."
According figures, 23pc of adults in Ireland are obese and a further 37pc are considered overweight.
One in every five children is heavier than is healthy.
The HSE said excess weight was also playing a key role in the severity of Covid-19 infection and that treatment and prevention must be prioritised.
The spokeswoman said: "People with obesity are particularly vulnerable to the effects of Covid-19 and appear to have a higher rate of serious complications from the virus."