The Ambulance service is struggling to find staff on St Mary's.
The need to attend a residential course and hold a C1 driving licence has proved a deterrent to potential applicants.
South Western Ambulance Service County Commander Geoff Griffin revealed the information in his report for this month's Scrutiny Committee.
He wrote: "It has been difficult over the years to increase the numbers of staff providing a response through a lack of interest and the inability for potential new recruits to be released from their full-time work to attend residential courses for a period of six weeks.
"We have recently run a recruitment campaign for Emergency Care Assistants on St Mary's... we are aware that one of the issues preventing more applicants relates to the requirement for a C1 driving licence, something that is not automatically applied by the DVLA since 1997 and through a lack of need is not routinely obtained by residents on the Isles of Scilly due to access and cost.
“We are currently researching ways of working around this without compromising safety, breaching driving regulations or placing the patient, staff or Trust at risk. Should we manage to accomplish this then we will look to run a further campaign.”
Geoff also revealed that there has been a declining number of community first responders on the off islands.
Scrutiny Committee chairman Avril Mumford said: "I think all of us here would like to send our grateful thanks to all the first responders and all the paramedics. We couldn't do without them."