"There were patients who had been waiting for two days ... It's at such a dangerous level the patients aren't getting the care they need through a lack of Government funding."
They said patients are supposed to be seen and treated within six hours of arrival, but often the emergency department is falling well short of the target.
At 11am on Monday, there were patients being seen to who had been in the waiting room since 9pm the night before, they said.
"The population in south Auckland has expanded so much that this hospital cannot cope."
College of Emergency Nurses NZ chairperson Sandy Richardson said such workplace pressures are unfortunately not unique to Middlemore, and are seen in other hospitals around the country.
"It's been building for a long time and it's reached a point where it's going to explode," Richardson said.
"We can't keep working like this."
During the parliamentary health select committee's annual review of the Counties Manukau DHB earlier this month, chief nurse Jenny Parr said the DHB had vacancies for 150 nurses.
She said the DHB was trying to juggle staff working in managed isolation facilities, while the country's closed borders meant access to overseas workers was restricted.
Labour MP Louisa Wall said chronic underfunding of the DHB had seen it shortchanged by over half a billion dollars over the past 21 years.
That was despite the fact its residents represent some of the most socio-economically deprived people in the country, with high rates of health problems such as diabetes, obesity and heart disease.
Health Minister Andrew Little said on Wednesday that the Government was preparing to urgently restructure the health system, which was under stress and riven with inequities.
Little said he plans to reform the sector in response to the Health and Disability System Review, which was released in June 2020.
He said at a function for health sector leaders at Parliament on Wednesday that Cabinet would decide next month on how to proceed.
"The system is under stress now ... and the situation is only going to worsen without reform," Little said.
Counties Manukau District Health Board was approached for comment.