More than 70 people who needed an ambulance in Melbourne on Thursday night were left waiting because there were none available.

Ambulance Union secretary Danny Hill says those left waiting “could be … code one cases, absolutely — so lights and sirens cases”.

The shocking delays came as a code red was declared in the ambulance service after a surge in demand and technology problems.

The computer-aided dispatch system, which is used to allocate crews to the nearest case, crashed.

Mr Hill said that meant call-takers were forced to “literally go to an old manual pen and paper system”.

“What we’re seeing at the moment is not just the high demand, we’re actually seeing a very inefficient use of our resources,” he said.

An ESTA spokesperson said “all code 1 cases were dispatched appropriately”.

“ESTA worked with Ambulance Victoria to resolve the [dispatch system] issue within about 30 minutes, which ensured minimal impact on ESTA’s service to the community,” they said in a statement.

Press PLAY below to hear about the concerning situation in the ambulance service last night

Code orange declared in Melbourne’s hospital system ‘two or three times per week’

Code orange declared in Melbourne’s hospital system ‘two or three times per week’