The union 'Unison' says the South Western Ambulance Service won't reach the standards everyone wants unless it gets more money.
In a report published today, the Hospitals' Inspector claims the region's ambulance service isn't good enough.
Although they rated many aspects as 'good' and one area 'outstanding' overall, they want improvements.
But Unison says quality could be hit further unless the government invests more.
They're working with ambulance management and health service bosses before the next inspection.