THIS scene outside Cairns Base Hospital's emergency department yesterday is another stark reminder why the region needs a new hospital, now.

Ten ambulances were queued outside the choked department by early afternoon, forcing frustrated paramedics to wait for up to three hours before unloading patients.

Officers said they had been putting up with the "bad old days" of no emergency beds for at least a week but yesterday's jam-up had gone from bad to worse as the day went on.

"It's beyond a joke," one told The Cairns Post. "Something's got to change."

Queensland Ambulance Service area director Warren Martin, who oversees a fleet of 12 vehicles across Cairns, Smithfield and Edmonton, said up to 10 ambulances were effectively out of action for hours.

The situation peaked about 2pm when several patients arrived around the same time, causing 10 or 11 ambulances to back up, Mr Martin said.

But he stressed that while the ambulance gridlock outside the emergency department, also known as "ramping", was still happening, new systems to fast-track patients were helping.

"It means that when we do ramp, it's not lasting as long," Mr Martin said.

"Today was just one of those days." All the patients forced to wait in ambulances yesterday were being closely monitored by emergency doctors, and were in the mid-urgency rather than high-urgency categories, he said.

"It's a bit of a cross-section, everything from gastro upset tummies to someone with abdominal pain … I think the hot weather back with a vengeance today has been knocking older people around a bit," Mr Martin said.

Mr Martin said he was "really looking forward" to next year's expected completion of a major expansion to the emergency department, which would double its size and add 12 more beds.

A Queensland Health spokesman attributed the delays to a rush of patients at once, with 30 arriving during the most intense period of 12.30pm to 3pm, or about 12 an hour.

On a normal day, the department averages five patients per hour.

The spokesman said his information was that the maximum number of ambulances waiting at one time had been eight.