Nearly 76,000 patients walked away from Emergency Departments last year without finishing their treatment.
According to Freedom of Information figures released to Newstalk, that is an increase of 66% on 2020.
The HSE says Emergency Departments are for people with serious injuries or illnesses, but many others go there when they do not need to.
It says patients are treated by priority and, because of that, some patients with less serious needs may choose to get healthcare elsewhere.
New figures show 75,547 people left Emergency Departments without finishing their treatment last year, compared to less than 46,000 the previous year.
Galway GP Martin Daly denies many people go to A&E when they do not need to.
"I think people go to access care where they're best able to access it.
"So if there's a shortage of GPs - if there are less avenues for people to access outpatient care in a timely manner - then people gravitate towards the only avenue into the hospital system, which is through the Emergency Room".
Stephen McMahon, from the Irish Patients Association, says: "In a lot of cases they're leaving because they haven't been seen after a lengthy period of time".
Tallaght and the Mater Hospitals in Dublin both had over 500 'Did Not Waits' last year.
The next highest was Our Lady Of Lourdes Hospital in Drogheda, at 459 - followed by University Hospital Limerick at 417.