A major health services union will have its paramedics refuse to work overtime at major sporting events in NSW until a pay dispute is settled.

The action, which began on Saturday, was continued in perpetuity after a meeting on Tuesday where Health Services Union (HSU) members deferred deciding on an offered four per cent pay rise as they seek better professional recognition.

Events most impacted will be horseracing and NRL finals. Instead of ambulances doing on-site standby duties, if there is an emergency an ambulance now won't attend until after someone dials triple-zero.

HSU members will also insist on clinical escorts for patient transfers, meaning a doctor or nurse will need to be in attendance when transferring high-risk patients.

The union says paramedics in NSW are continuing to be treated as if they only drive ambulances, when in reality their clinical and public health responsibilities have "skyrocketed" over the past decade.

One example is paramedics now performing diagnostic procedures and administering medicines to prevent someone suffering a heart attack from deteriorating, saving the taxpayer tens of thousands of dollars in hospital costs, according to the union.

"Paramedics are more than a line item on a spreadsheet. They are an indispensable part of the health system," HSU NSW secretary Gerard Hayes said.

"It's time they are paid what they are worth."

With NSW paramedics earning less than their interstate counterparts, Mr Hayes said an "attraction and retention" crisis could worsen if pay doesn't begin to reflect skills.

"The drift of paramedics interstate will become a torrent unless we fix this problem," he said.

The NSW Health Minister has been contacted for comment.